This is one of those cakes that I inevitably end up having for breakfast but that should never be served for breakfast. It is a full on honest-to-goodness cake with sugar and butter and decadent frosting.
In a separate bowl with a handheld mixer cream together the brown sugar, the peanut butter, and the butter.
Add in the flour mixture alternately with the milk, beating well after each addition, and gently stir in 1/2 cup of the chopped chocolate.
Pour batter into a prepared 8-inch round cake pan and bake at 350 degrees for 28-34 minutes, or until a tester comes out clean.
If you are adding peanut butter glaze, turn the cake out directly onto a cake stand and add glaze while cake is still slightly warm.