Preheat your oven to 350°F (175°C). Line a 15x10-inch jelly roll pan with parchment paper.
In a medium-sized bowl, whisk together the flour, cocoa powder, baking powder, and salt.
In a large bowl, beat the eggs and sugar together with an electric mixer on high for 5 minutes until thick and pale.
Add vanilla extract and fold in dry ingredients gently.
Pour batter into the prepared pan and bake for 10-12 minutes or until a toothpick comes out clean.
While the cake bakes, dust a clean kitchen towel with powdered sugar.
Once baked, invert the cake onto the towel and remove parchment paper. Roll up the cake with the towel inside and let it cool.
For the filling: whip the heavy cream with powdered sugar to soft peaks, then gently fold in the chopped Ferrero Rocher, crushed Oreos, and M&M’s.
Unroll the cooled cake and spread the filling evenly, then roll it back up.
For the ganache: heat heavy cream until it simmers, then stir in chocolate chips until smooth. Let cool before pouring over the cake.
Decorate with extra M&M’s, crushed Oreos, and Ferrero Rocher.
Allow the ganache to set before slicing and serving.