Preheat oven to 350 degrees. In a 8″ x 8″ or 9″ x 9″ pan, add 1 cup flour.
Add 1 cup sugar.
Add 2 tablespoons unsweetened cocoa powder.
Add 2 teaspoons baking powder.
Add 1/4 teaspoon salt.
Using a spoon or other tool, form a well in the center of the pan’s ingredients.
Add 1/2 cup milk to center well.
Add 2 tablespoons vegetable oil.
Add 1 teaspoon vanilla. Stir thoroughly until smooth.
Chop 1 cup walnuts.
Spread the walnuts across the mixture.
Add 1 cup brown sugar, distributing evenly across pan.
Add 1/4 cup unsweetened cocoa powder.
Add 1 3/4 cup hot water. Just add to the top, don’t stir.
Place in preheated 350 degree oven for 40 minutes.
Remove from oven and allow a few moments to cool. Flip over pieces onto plate. Cake is best served warm. Sauce will be at bottom of pan. Add whipped topping, walnuts, and other toppings as desired. Serve and enjoy!