Bon Appetit magazine, but I just hesitated because I have never made brownies with browned butter. I do like browned butter on pasta, but have not tried it in a cake or brownie recipe. Browned butter does have a rich, and nutty flavor, so why not add it in the brownies. Also, one other important result, that the recipe did promise, is the fudgy and chewy outside, with a shiny, crackly top. Just look how it turned out...yumm! It was not very popular with my little ones, (my grandchildren)...my grandson was trying to pick out the walnut pieces, but I had one cup of toasted walnut pieces in the batter. It did not call for toasting the walnuts, but I know that toasting nuts would release the oils from the nuts, and would make it more tasty, and crunchy.