I was going to say the same as Jodi regarding over cooking biscuits. I used to do the same thing... over cook... until i followed a Mrs Fields white chocolate and macadamia nut recipe. I followed it to the letter and was very surprised to note that when i took them out of the oven they were soooo fragile. But i let them cool as per the recipe and sure enough the sugars "set" and made the biscuit firmer when at room temp. I also now use baking paper a lot... helps the bottoms stop from going too dark.