Equipment
- 18x13 sheet pan I recommend 3 pans
- large slicing knife specific knife mom uses for dobos to get clean slices
Ingredients
Chocolate Diplomat Cream
- 150 grams unsalted butter, softened
- 42 grams semi-sweet chocolate chips
- 4 large egg yolks, room temperature
- 67 grams granulated sugar
- 10.5 ounces Cool Whip, *see blog post for using homemade whipped cream
- 10 grams cocoa powder, dutch or natural is fine
- 1 Tbsp rum essence
Sponge Cake
- 120 grams all-purpose flour, sifted
- 6 large egg whites
- 30 mL cold water
- 100 grams granulated sugar
- 6 large egg yolks
- 80 mL canola oil
Chocolate Glaze
- 130 grams semi-sweet chocolate chips
- 80 mL canola oil
- 10 mL milk
Burnt Sugar
- 200 grams granulated sugar
- 120 mL water
Method
Chocolate Diplomat Cream
- In a medium saucepan (preferably stainless steel or nonstick – avoid aluminum), heat the butter for a minute until it starts to melt, then add in the chocolate chips and stir until the chocolate is fully melted. Set aside.150 grams unsalted butter softened, 42 grams semi-sweet chocolate chips
- In a medium bowl, whisk together the egg yolks and sugar aggressively for a minute, until the mixture becomes smooth and runny, with no more chunks.4 large egg yolks room temperature, 67 grams granulated sugar
- Temper the eggs by streaming the butter and chocolate mixture into the egg yolk mixture, while continuing to whisk.
- Dump the whole mixture back into the saucepan and cook over medium-low heat, while whisking continuously. Within a few minutes, the mixture should start to thicken, now whisk aggressively for another 30-60 seconds. Remove from the heat and pour into a bowl.
- Cover with plastic wrap and set aside to cool completely (this may take several hours - I don't like to refrigerate it because then it gets too firm. *I usually make my cakes during this time*).
- Once the custard has cooled, place the custard, Cool Whip, rum and cocoa powder into the bowl of a stand mixer or a large bowl with the hand mixer and beat until it's well combined.10.5 ounces Cool Whip *see blog post for using homemade whipped cream, 10 grams cocoa powder dutch or natural is fine, 1 Tbsp rum essence
Sponge Cake
- Preheat the oven to 400F (204C) convection and generously grease 3 18x13 sheet pans with baking spray or oil and line them with parchment paper.
- Sift the flour into a bowl and set aside. Then separate the egg whites and egg yolks.120 grams all-purpose flour sifted
- On medium speed, begin beating the egg whites and water and slowly add in the sugar, like the start of a meringue. Beat until it is fluffy - about doubled in size.6 large egg whites, 100 grams granulated sugar, 30 mL cold water
- Add in the egg yolks and the oil and beat until they're fully combined.80 mL canola oil, 6 large egg yolks
- Turn the mixer to medium speed and spoon in the flour. This is important because if you add all of it (or even half at a time) it clumps together. Use a rubber spatula to scrape the edge of bowl well and make sure all the flour is mixed into the batter.
- Use 1/3 of the batter in each pan - it should be roughly 7 ounces of cake batter for each cake layer. Make sure to go all the way to the edge, and spread it out as evenly as possible so it bakes evenly.
- Bake for about 5-7 minutes, until it's golden - not white and not brown so keep a close eye on it. Remove from the oven and let it rest in the pan for a few minutes. I leave it in there until I'm ready to assemble but if you're making a larger quantity, transfer them out of the pan with the parchment paper after a couple of minutes.
Assemble
- Slice the sponge cakes into three long rectangles each. I do it from short end to short end so they're long and skinny.
- Place the first layer onto a flat surface and then spread a layer of the cream on top. The cream should be roughly as thick as the cake - I used 3 small scoops which totaled to about 2.6 ounces of cream per layer.
- Repeat until you've reached the top layer - don't frost the top layer. Refrigerate the cake for several hours or overnight. The fridge is fine for the chocolate glaze but I recommend freezing it if you're doing the burnt sugar topping.
Chocolate Glaze
- Place the chocolate chips, oil and milk in a small saucepan over medium-low heat.130 grams semi-sweet chocolate chips, 80 mL canola oil, 10 mL milk
- Stir until it's completely smooth and pour on top of the cake. Spread it out evenly, drizzle along the edge. To even the top perfectly, lightly tap the cake on the counter. Chill the cake again until the chocolate is completely set.
Burnt Sugar Topping
- Melt the sugar and water in a small saucepan over medium-low heat. Swirl the pan so it melts evenly.200 grams granulated sugar, 120 mL water
- Once it starts to brown, swirl the pan a little to make it brown evenly.
- Once it reaches a golden amber color remove it from the heat and let it rest for a minute.
- Slowly pour it on top of the FROZEN cake.
- While it's still hot, use a large serrated knife to score the sugar topping - don't slice through, just create little lines to help slice later. My mom greases her knife between each one so it doesn't stick to the sugar. Slice after after it's completely set.
- To slice, use a large non-serrated knife, run it under hot water, and wipe it dry between every single slice. This will ensure clean slices.
The hot sugar makes the sponge shrivel a little once it hardens so save your largest slice of cake for the top layer to avoid it getting smaller than the layers underneath.
Notes
Do not discard the edges - they are THE BEST part of the cake that my kids and I fight over!!
Nutrition
Serving: 1gCalories: 351kcalCarbohydrates: 27gProtein: 5gFat: 25gSaturated Fat: 10gPolyunsaturated Fat: 4gMonounsaturated Fat: 11gTrans Fat: 0.4gCholesterol: 141mgSodium: 40mgPotassium: 132mgFiber: 1gSugar: 18gVitamin A: 430IUCalcium: 47mgIron: 1mg
