Preheat your oven to 350°F (175°C). Prepare a jelly roll pan by lining it with parchment paper.

In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking powder, and salt until well combined.

In a large mixing bowl, beat the eggs and granulated sugar together for 4 to 5 minutes until thick and creamy. Gradually mix in the vegetable oil, milk, and vanilla extract.

Gently fold the dry ingredients into the wet mixture using a spatula until just combined.

Pour the batter evenly into your prepared jelly roll pan and bake for 10-12 minutes.

Remove the cake from the oven and turn it out onto a sugared kitchen towel. Carefully roll the cake up with the towel inside and let it cool completely.

In a separate bowl, combine the creamy peanut butter with powdered sugar, then add heavy cream and vanilla extract. Beat until smooth, then gently fold in chopped peanut butter cups.

Once cooled, unroll the cake and spread the peanut butter filling evenly over the surface. Roll the cake back up tightly and place seam side down.

In a small saucepan, heat heavy cream until hot but not boiling. Pour the hot cream over the semi-sweet chocolate chips and stir until smooth.

Drizzle the chocolate ganache over the assembled roll and refrigerate for about 30 minutes to set.