Baking – Uneven brownie baking

If they're tangier than you'd like that would be due to the acidity of the cream of tartar. While most recipes for Snickerdoodles do in fact us cream of tartar and baking soda for a homemade form of baking powder (most likely due to the fact that snickerdoodles are fairly "old"-style cookie), a few I looked at are using baking powder and no cream of tartar.

Here are a few things to know and a suggestion:

Acidic doughs do not spread easily and do not brown easily. Using the combination of cream of tartar in the 2:1 ratio w/ baking soda for leavening not only causes them to puff but with the higher acidic ratio it is also likely to help in keeping them more "cakey" and prevent them from browning as much.

You could try cutting back the cream of tartar slightly and seeing if that helps (possible drawback could be the soda making a more pronounced bitter soapy taste if there isn't enough acidity).

Or

Replace the cream of tartar and baking soda with baking powder. Baking powder by volume isn't as powerful as baking soda because of the fact it contains soda, two dry acids, and cornstarch. 1 teaspoon of baking powder will leaven 1 cup of flour (vs. 1/4 teaspoon of baking soda to leaven a cup of flour). If your recipe calls for 2 cups of flour then use 2 teaspoons of baking powder and cut out the cream of tartar and baking soda.

One of the most important factors in achieving a fudgy, chewy brownie is cooking time. Essentially you should be slightly undercooking the brownies so they don't dry out in the middle.

Use the cooking times given in recipes as a guide only, because each oven will vary. 5-10 minutes before they 'should' be ready, start testing the centre of the brownies with a toothpick or cake tester: unlike a cake, you want a good amount of sticky crumbs on the skewer (but very little liquid batter). Remember that the cooking process will continue even once the brownies are out of the oven.

Another factor that contributes to chewiness is the sugars you use: adding some sticky, dense, dark sugar will help create a fudgy brownie. The brownie recipe I use, which is pretty damn good, uses 1.5 cups of granulated sugar and .5 cup of packed dark brown sugar.