Cookies problems, diagnosed

Cookie bottoms usually burn because the sheet pan is too dark or hot, the rack is too low, the oven has a strong bottom hot spot, or the cookies stay on the hot tray too long.

Cookies turn cakey instead of chewy when the dough traps too much air, contains too much flour or egg, or uses a formula that favors lift over spread.

Flat cookies happen when the dough spreads before enough structure forms to hold the cookie shape. Check dough temperature, ingredient balance, baking-sheet temperature, the baking surface and actual oven temperature before changing the whole recipe.

Cookies usually turn hard or dry because they were baked too long, measured with too much flour, baked too hot, or stored where they kept losing moisture.