For this week’s Please Explain, we’re following dogs as they sniff their way through the world with their incredible sense of smell. Alexandra Horowitz, who teaches canine cognition and creative nonfiction at Barnard College and runs the Horowitz Dog Cognition Lab, explores the abilities of a dog’s nose, how it’s evolved, how it’s being put to use and how we can improve our own sense of smell. Her latest book is Being a Dog: Following the Dog Into a World of Smell.  Note: Jonathan Capehart guest-hosted this segment of "The Leonard Lopate Show."

How did cats get domesticated? Why are they so popular on the internet? Are they good or evil? If you have wanted to know the answers to these questions, and more, tune in to our latest Please Explain, which is all about cats. We're joined by Abigail Tucker, correspondent for Smithsonian Magazine, and author of The Lion in the Living Room: How House Cats Tamed Us and Took Over the World.

There are over 200 varieties of peppers, ranging from shishitos to habaneros. For our latest Please Explain, we dig into the world (and health benefits) of peppers with three-time James Beard Award-winning chef, culinary historian and author Maricel Presilla. She’s the author of Peppers of the Americas: The Remarkable Capsicums That Forever Changed Flavor, which explores the history of peppers and the many dishes you can make with them.

Vinegar often plays an essential role in the food we eat. We use it in everything from baking to braising to pickling. But, author Michael Harlan Turkell writes that vinegar is "underappreciated and little understood." For his new book Acid Trip: Travels in the World of Vinegar: With Recipes from Leading Chefs, Insights from Top Producers, and Step-by-Step Instructions on How to Make Your Own, Turkell set out to give vinegar its due. He traveled the world, learning how countries from Japan to France make and use vinegar. He also collected recipes from chefs who are using vinegar in exciting, different and delicious ways. He joins us for our latest Please Explain to discuss vinegar's many uses and how you can make your own at home. Micheal Harlan Turkell will appear in conversation with Francine Segan, Ivan Orkin and Neil Kleinberg at the 92nd Street Y (1395 Lexington Ave. at 92nd St.) on Dec. 7 at 7 p.m. Check out a recipe from Michael Harlan Turkell's Acid Trip below! OEUFS EN MEURETTE, FROM BERTRAND A UBOYNEAU, BISTROT PAUL BERT, PARIS, FRANCE SERVES 4 This dish takes the concept of bourguignon sauce and uses it to poach eggs. What you’re left with is the same rich stock, adding the decadence of a creamy egg yolk, with a side of toast to sop it all up. Bertrand, always in need of acidity, uses a portion of red wine vinegar in place of some of the red wine, which gives a much lighter quality to a dish that usually invites a postprandial nap, and instead has you feeling like conquering the day ahead. ¼ pound (115 g) THICK SMOKED BACON, cut into lardoons 1 tablespoon BUTTER ¼ pound (115 g) WHITE PEARL ONIONS, peeled, tops and bottoms trimmed 1 clove GARLIC, crushed ¼ pound (115 g) BUTTON MUSHROOMS, cleaned, cut into quarters 3 cups (720 ml) RED WINE, such as Burgundy, Beaujolais, Cabernet 1 branch THYME 1 cup (240 ml) RED WINE VINEGAR 4 EGGS, kept in shell, cold BLACK PEPPER PARSLEY LEAVES, optional TOAST and BUTTER   In a large saucepan over medium heat, render the bacon for 5 to 7 minutes, until it’s just browning but not burning. If it’s cooking too fast, lower the temperature. Pour out all but about 1 tablespoon of the fat (reserve the excess to cook with another time) and set the bacon aside (you’ll add it back in later, so try not to snack on it too much). Add the butter, onions, and garlic and cook for about 1 minute, until aromatic. Lower the heat to medium-low, add the mushrooms and cook for another 2 minutes, stirring occasionally. Add the red wine, scrape the bottom of the pan to release the fond, and add the thyme. Bring back to a simmer and cook for 45 minutes, or until reduced by a third. Add the red wine vinegar and continue to cook for another 30 minutes. (If it’s too acidic for your taste, add ¼ cup water at a time until it’s not.) To poach the eggs, either in the pot of sauce itself (if you don’t mind a few stray pieces of egg white) or in a separate pot of water, bring the liquid to a bare boil. Make a small pinprick on the larger end of each egg, place in the liquid, and cook for 30 seconds (a Julia Child tip); this is just to set the whites. Remove the eggs and crack them into individual small bowls. Slide the eggs back into the pot to poach them. If you like a soft yolk, cook for only a few minutes. Using a slotted spoon, remove the eggs and set aside. In individual serving bowls, evenly distribute the onion and mushroom mixture, then pour a bit of the sauce, enough to cover an egg, into the bowl as well. Place the eggs into the bowls and garnish with the bacon, freshly cracked black pepper, and parsley, if using. Bon appetit! Note: Jonathan Capehart guest-hosted this segment of The Leonard Lopate Show.

For this week’s Please Explain, James Peterson stops by to talk sauces. He’s an award-winning food writer, cookbook author, photographer and cooking teacher who started his career as a restaurant cook in Paris in the 1970s. His book, Sauces: Classical and Contemporary Sauce Making, has just been released in its fourth edition. James will answer all of our burning sauce-related queries – from béarnaise and hollandaise, to bolognese, crème anglaise, and everything in between.  Check out some of James Peterson's sauce recipes below! SAUCE BÉCHAMEL The amount of roux per given amount of milk depends on the use of the sauce. Thick  versions,  used  as  the  base  thickener  in  traditional  soufflé  recipes,  often  call  for  as  much  as  8  ounces  (250  grams)  of  roux  per  quart  (liter)  of  milk,  whereas  béchamel-based  soups  use  approximately  2  ounces  (60  grams)  per  quart  (liter)  of  milk. This recipe produces a medium-thick sauce, appropriate for vegetable gratins. YIELD: 1 QUART (1 LITER) INGREDIENTS                                                                    milk           1 quart                  1 liter butter        3 ounces              90 grams flour          ¹⁄³ cup                  80 milliliters seasonings (salt, pepper, nutmeg; optional)      to taste                to taste 1. Bring  the  milk  to  a  simmer  in  a  2-quart  (2  liter)  saucepan.  Whisk  it  from  time  to  time  to  prevent  a  skin  from  forming  on  its  surface  (see  Note). 2. In a second 2-quart (2 liter) saucepan, gently melt the butter and add the flour. Stir the butter and flour over medium heat for about 2 minutes, until the flour has a pleasant, toasty smell. (A) Remove from the heat for about 30 seconds to cool slightly. 3. Whisk the simmering milk into the roux.  Return the sauce to the stove and bring it back to a simmer while whisking. (B) 4. Once  the  sauce  has  returned  to  a  slow  simmer, turn down the heat and move the saucepan so  that  only  one  side  is  over  the  flame.  (This will cause a skin to form on only one side of the sauce’s surface, making it easy to skim.) Cook the sauce gently for 30 minutes to 1 hour, skimming off the skin. It is a good idea also to occasionally rub around the bottom and corners of the sauce-pan  with  a  wooden  spoon  to  prevent  the  sauce  from scalding. 5. When the starchy taste has cooked out of the sauce, it can be seasoned and strained, depending on its final use.  Béchamel should be stirred while it is cooling to prevent a skin from forming on its surface. Putting the pan over a tray of ice will, of course, speed cooling. Note: Some chefs do not first bring the milk to a simmer and instead pour cold milk, all at once, over the roux.  This  method  saves  time—and  a  pot—but  be  sure  to  whisk  the  sauce  vigorously  to prevent lumps and skin from forming. VARIATIONS Use a pretreated flour such as Wondra.  Simply  mix the  Wondra  (the  same  amount  as  flour  called for in the traditional recipe) in cold water until  smooth  (make  a  slurry).  Bring the milk to a simmer. Whisk in the slurry. Simmer until the sauce thickens. It should be smooth, but just in case, work it through a chinois. While béchamel is a fairly stable sauce, there are times  (especially  if  the  flour  is  old)  when  it  will  break.  To avoid this, blend hydrocolloids into the finished sauce.  Lambda  carrageenan  lends  an  authentic  dairy-like  mouthfeel  to  the  sauce  and  is  easy  to  use.  Start by adding 1%  lambda  carrageenan to the sauce and build up as needed to get the thickness you want.   James Peterson's cauliflower gratin. (Courtesy James Peterson)   CAULIFLOWER GRATIN Béchamel  derivatives,  especially  Mornay  sauce,  make  excellent  toppings  for  gratins  because  they  brown  and  become  extremely  aromatic.  Practically any  vegetable can be pre-cooked slightly and then baked while covered with sauce. YIELD: 6 SERVINGS INGREDIENTS                                                                    cauliflower, 1 large bunch or 2 small bunches mornay sauce (SEE BELOW)                 1 quart                               1 liter grated gruyère or similar cheese          1½ cups                              180 grams 1. Preheat the oven to 350°F (180°C).  Cut the cauliflower into florets. Boil for about 5 minutes. Drain and transfer to a gratin dish just large enough to hold the cauliflower in a single layer. 2. Ladle the Mornay sauce in an even layer over the cauliflower. (A) 3. Sprinkle the cheese over the gratin.  (B)  Bake  until  a  golden  crust  forms  on  top,  about  30  minutes. SAUCE MORNAY Sauce  Mornay  is  usually  used  as  the  base  for  cheese  soufflés  or  for  gratins.  When  it  is  used  for  gratins,  additional  cheese  and  sometimes  breadcrumbs  and  butter  are  added  to  its  surface  to  encourage  the  formation  of  a  crust.  Sauce Mornay is made by adding grated cheese to sauce béchamel. Be sure to choose a full-flavored, well-aged cheese for this sauce. If the cheese is too young, the sauce will not only lack flavor but will be stringy. Classic  recipes  use  half  grated  Gruyère  and  half  grated  Parmesan  (at  least  three-year-old  Parmigiano-Reggiano),  but  the  sauce  can  be  made  with  other  well-aged,  honest  cheese.  English farmhouse Cheddar and Vermont Cheddar (not the commercial kind that has been dyed orange) both work well. Blue cheeses can also be incorporated into Mornay sauces, but be sure to taste and select them carefully to avoid some of the poor-quality  versions  that  have  a  coarse,  sour-milk  smell  and  flavor.  Select genuine Roquefort, Stilton, Gorgonzola, Fourme d’Ambert, or Bleu d’Auvergne. Keep in mind that blue cheeses tend to make sauces a bit gray. To  prepare  Sauce  Mornay,  add  approximately  4  ounces  (115  to  125  grams)  cheese  per quart (liter) of béchamel. Stir the sauce just long enough for the cheese to melt; over-cooking the cheese can cause it to turn stringy. Some recipes call for finishing Mornay with egg yolks (about 2 per quart/liter of sauce). This is useful if the sauce is being used as a base for cheese soufflé, but otherwise the yolks contribute little to the sauce except unnecessary richness. At times, if the cheese is too young, a Sauce Mornay may break. To avoid this, you can  blend  hydrocolloid  stabilizers  (0.15%  percent  xanthan  gum  and  1%  lambda  carrageenan) into the béchamel before adding the cheese. These recipes came from Sauces: Classical and Contemporary Sauce Making by James Peterson. © Copyright 2017 by James Peterson. Used by permission of Houghton Mifflin Harcourt. All rights reserved.