01 -
Preheat oven to 175°C. Lightly grease a 23 x 33 cm glass baking dish to ensure even heat distribution.
02 -
Mix chocolate cake batter according to package instructions, adding the specified water, oil, and eggs. Blend until smooth, then pour evenly into the prepared baking dish.
03 -
In a large bowl, beat softened cream cheese and melted butter until fully smooth. Add creamy peanut butter and vanilla extract, mixing until incorporated. Gradually blend in powdered sugar until creamy and thick.
04 -
Distribute spoonfuls of the peanut butter cream mixture across the surface of the cake batter. Leave swirls visible without mixing into the base.
05 -
Scatter semi-sweet chocolate chips and halved mini peanut butter cups evenly over the top. Gently press some pieces into the batter, ensuring most remain on the surface.
06 -
Bake for 45 to 55 minutes, or until the edges are set, the top is cracked, and the center is just firm with a light jiggle. Baking times may vary; monitor closely during the final minutes.
07 -
Allow to cool slightly before serving. Enjoy warm for a gooey texture, or let cool completely for neat slices.