This is one of the best tips I will ever share! All it means is stack two baking sheets together and top the second one with parchment paper. This extra pan preparation ensures cookies bake thoroughly and evenly. The tops will be done while the bottoms stay tender and gently browned, never a burnt bottom or too-brown edges with this method. As holiday cookies are also extra rich with butter and sugar, they tend to brown faster. If you learn nothing else from this little cookie book, remember this great secret tip which works just as well on all your cookies, not just at holiday time.