Make the Cake: preheat oven to 350°F. Line a jelly roll (10x15”) pan with foil and spray with cooking spray (I like to use the spray with flour).
Beat eggs at high speed for 3 minutes, until frothy and dark yellow. Beat in sugar, coffee or water, and vanilla extract. Mix in cocoa, salt, and baking powder, then mix in flour. Stir just until blended.
Spread in prepared pan. Batter will be in a very thin layer and you will need to use a wooden spoon or spatula to spread it to all the corners of the pan. Bake for 10-15 minutes. You’ll know it’s done because if you lightly poke the top with your fingertip it will slightly bounce back.
While the cake is baking, set a clean kitchen towel out on a large work surface. Sprinkle liberally with powdered sugar (about 1/4 cup). As soon as the cake comes out of the oven, turn it over on the kitchen towel sprinkled with powdered sugar. Remove foil carefully.
Working at the short end, fold the edge of the towel over the cake. Roll tightly, rolling up the cake into the towel. Let cool completely while rolled, at least one hour (or you can wrap it and chill it overnight).
Make the Filling: beat cream cheese and peanut butter with a hand mixer until smooth. Beat in powdered sugar until crumbly, then add vanilla and 2 tablespoons heavy whipping cream. Mix until smooth and a spreadable consistency, adding up to 2 additional tablespoons of heavy whipping cream. Stir in 1/2 cup chopped peanut butter cups.
Assemble Cake: Unroll the cooled cake carefully and then spread the filling on the cake, leaving 1” without filling at either end. Re-roll cake, scooping out any filling that spills out as you roll. Cover with plastic wrap and chill for at least one hour before frosting.
Make the topping: place chocolate chips and 2/3 cup heavy whipping cream in a microwave safe bowl or measuring cup. Microwave for about 30-60 seconds, then whisk until smooth. Chill for about 20 minutes or freeze for 10, until it thickens to a pourable but not watery consistency.
Place cake roll on a wire rack set over a cookie sheet. Pour the ganache over the cake evenly. Top with remaining chopped peanut butter cups. Chill until set. Slice and serve.
May be stored, wrapped in plastic, in the refrigerator for 24 hours before serving.
It’s better to overbake the cake then under bake it.
Roll it while it’s hot. (That’s a song, right?)
If you don’t get powdered sugar all over the far wall of your kitchen when you flip over your cake, you may not have used enough on your towel. 😉
Again, roll it while it’s hot. (I can’t help it, it’s catchy.)
Be sure to chill it before you frost and or slice it. This gives the filling time to firm up a bit so it doesn’t squish out when you cut it.
You can always top this with a sprinkle of powdered sugar instead of ganache.
If it cracks, it could be for so many reasons. Not cooked enough, over cooked, humid air, dry air, Mercury is in retrograde, etc. Just use some filling to paste it together and add more ganache and peanut butter cups on top. NO ONE WILL KNOW.