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...