1. Make the Chocolate Sponge Cake

1. Preheat oven to 350°F (175°C). Line a 10×15-inch jelly roll pan with parchment paper.
2. In a bowl, whisk together flour, cocoa powder, baking powder, and salt.
3. In another bowl, beat eggs and sugar on high speed for 3-4 minutes, until thick and pale.
4. Mix in vanilla, oil, and milk. Gently fold in the dry ingredients until combined.
5. Spread batter evenly in the prepared pan.
6. Bake for 12 minutes, or until the cake springs back when touched.

2. Roll the Cake While Warm

1. Lay out a clean kitchen towel and dust with powdered sugar.
2. Flip the warm cake onto the towel, then peel off the parchment paper.
3. Roll the cake (with the towel) into a tight log and let it cool completely.

3. Make the Cookie Dough Filling

1. Heat-treat the flour by baking it at 350°F (175°C) for 5 minutes or microwaving for 60 seconds, stirring halfway. Let cool.
2. In a bowl, beat butter and brown sugar until smooth.
3. Mix in milk, vanilla, and flour. Stir in mini chocolate chips.

4. Assemble the Roll Cake

1. Unroll the cooled cake and spread the cookie dough filling evenly over it.
2. Carefully roll the cake back up without the towel.
3. Wrap in plastic wrap and chill for 30 minutes to set.

5. Make the Chocolate Ganache

1. Heat heavy cream until steaming (not boiling). Pour over chocolate chips.
2. Let sit for 2 minutes, then stir until smooth. Mix in butter for extra shine.

6. Coat & Serve

1. Pour the ganache over the chilled cake and spread evenly.
2. Garnish with extra mini chocolate chips or cookie crumbles.
3. Slice and enjoy!