From the Back in the Day cookbook via Serious Eats , slightly edited
2 c rice flour mix
1 t baking powder
3/4 t xanthan gum
1/4 t salt
2 sticks melted butter (we used 1 1/2 and 4 T olive oil)
2 c packed brown sugar
2 room temp eggs (run them under warm water)
2 T vanilla (we weren't messing aroung)
2 T whiskey (or booze of your choice)
a package of good chocolate chips
Preheat the oven to 350 and line a 9x13 pan with foil or parchment and grease. Mix together the flour mix, baking powder, xanthan gum and salt. In another bowl, mix the butter and brown sugar. Beat in the eggs, vanilla and whiskey, then stir in the flour mix and the chocolate chips. Spread into the pan and bake 20-22 minutes. The top will get all delicious and crackley and the insides will be a little gooey still, like great chocolate chip cookies.
Cool completely and devour.