1. Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish thoroughly.
2. In a large mixing bowl, combine the devil’s food cake mix, melted butter, and egg until a thick dough forms. Firmly press this mixture into the bottom of your greased baking dish.
3. Gently microwave the creamy peanut butter for about 30 seconds until smooth. Evenly drizzle the peanut butter over the cake base layer.
4. Evenly pour the sweetened condensed milk on top of the peanut butter layer.
5. Sprinkle the dark chocolate chips and chopped pecans over the top of the cake.
6. In a small saucepan, warm the heavy cream over medium heat until it starts to simmer. Remove from heat, and whisk in the dark cocoa powder and confectioners’ sugar until smooth. Drizzle this chocolate sauce over the entire cake.
7. Bake the cake in the preheated oven for 25-30 minutes. The edges should be set, but the center should remain deliciously gooey.
8. Allow the cake to cool slightly before cutting into slices for serving.