Preheat your oven to 175°C (350°F) and line a 10x15-inch jelly roll pan with parchment paper, leaving overhang on the sides.

In a medium bowl, whisk the flour, cocoa powder, baking powder, and salt.

In a large bowl, beat the eggs and sugar together until thick, pale, and tripled in volume. Mix in the vanilla extract, oil, and milk gently.

Fold in the dry ingredients carefully to avoid deflating the batter. Pour the batter into the pan, spread evenly, and bake for 10–12 minutes or until it springs back when touched.

Lay a clean kitchen towel on the counter and dust it with powdered sugar. Turn the hot cake onto the towel, peel off the parchment paper, and roll it up tightly with the towel. Let it cool completely.

To make the filling, beat the peanut butter and butter together until smooth. Add powdered sugar and salt, and beat again. Add cream a tablespoon at a time until it’s fluffy and spreadable.

Unroll the cooled cake gently and spread the peanut butter filling evenly to the edges. Roll it back up without the towel and wrap tightly in plastic wrap. Refrigerate for at least 1 hour.

Heat the cream until simmering and pour it over the chocolate chips. Let it sit for 1–2 minutes, then stir to make a smooth ganache. Cool slightly before pouring it over the cake.

Decorate the top with crushed peanut butter cups and chill for 15 minutes before slicing and serving.