In a large mixing bowl, combine the chocolate cake mix, melted butter, milk, and peanut butter. Use a whisk or spatula to stir the ingredients together until the mixture is well combined and smooth. The aroma of chocolate and peanut butter will fill your kitchen!
Prepare the Baking Dish
Pour the batter into the prepared baking dish, spreading it evenly with a spatula.
Add the Toppings
Sprinkle the chopped mini peanut butter cups, chocolate chips, and optional crushed peanuts evenly over the top of the batter. The toppings will create a delightful layer of flavor and texture.
Bake
Place the baking dish in the preheated oven and bake for 35-40 minutes. Keep an eye on it; the cake is done when it is set and the edges are a beautiful golden brown, while the center remains soft and gooey.
Cool and Serve
