Preheat oven to 350° F. Grease a 9 x 9 inch baking pan
Put butter and chocolate chips in a microwave-safe bowl and heat for 30 seconds, stir and microwave for another 30 seconds. Repeat if necessary to melt the chocolate chips.
½ cup butter, 1 cup semi-sweet chocolate chips
In a large mixing bowl combine melted chocolate with brown sugar and eggs. Stir in Dr. Pepper and vanilla extract.
1 cup brown sugar, 3 large eggs, ¼ cup Dr. Pepper soda, 1 teaspoon vanilla extract
Add flour, cocoa powder, instant coffee, baking soda and salt. Stir just until combined.
1 cup all-purpose flour, 1 teaspoon instant coffee, ⅓ cup cocoa powder, 1 teaspoon baking soda, ½ teaspoon salt
Pour into prepared baking pan. Decorate the top with pecan or walnut halves if desired.
pecans or walnut halves
Bake for 35 to 45 minutes, let stand for 5 minutes in the pan and transfer to a cooling rack.