Chocolate Marshmallow Cake, also known as Penguin Cake — a super moist chocolate sponge soaked with a tea-and-rum mixture, topped with a homemade marshmallow layer and finished with a dependable chocolate glaze.
Chocolate Marshmallow Cake ranks among my top three favorite cakes. I first learned this recipe from my cousin D. years ago when we were beginners in the kitchen, and I’ve made it so often since then that I’ve lost count.
The dessert features a tender chocolate sponge soaked with a fragrant tea-and-rum syrup that keeps it exceptionally moist. A marshmallow topping is prepared from scratch (no store-bought marshmallows), and the cake is finished with a smooth chocolate glaze.
Over the years I noticed a pattern: the marshmallow topping turns out perfectly in cool, dry weather but can become grainy and separate into solid and liquid parts in hot, humid conditions. The problem stems from humidity — meringue-based toppings are sensitive to moist air, which can prevent egg whites from holding their structure. If you live in a very humid climate, this is likely the cause of any issues with the marshmallow layer.
One important step is pouring the tea mixture over the hot cake. I usually add 2–3 tablespoons of rum to the tea; if you prefer not to use alcohol, plain tea works fine. Use black, green, or rooibos tea for best flavor — herbal or fruity teas may clash with the chocolate. You don’t need to wait for the cake to cool before adding the tea or spreading the marshmallow topping, but the cake should cool before pouring the chocolate glaze so the glaze sets properly.
I hope you enjoy this cake as much as we do — it’s rich, comforting, and reliably delicious when prepared with attention to humidity and temperature.
Chocolate Marshmallow Cake, aka Penguin Cake — a super moist chocolate sponge soaked with a tea-and-rum mixture, topped with a homemade marshmallow layer and a foolproof chocolate glaze.
Dessert
American
chocolate marshmallow cake
- CHOCOLATE SPONGE:
-
2
cups
all-purpose flour -
2
tsp
baking powder -
1/3
cup
cocoa powder -
1
cup
butter or margarine
about 190 g (1–1½ sticks) -
1
cup
sugar -
4
large egg yolks -
1
cup
milk -
1 1/4
cup
tea + 2–3 Tbsp rum - MARSHMALLOW TOPPING:
-
4
large egg whites -
1 1/2
cup
sugar - CHOCOLATE GLAZE:
-
3 1/2
oz
chocolate
about 100 g, 43% recommended -
3 1/2
oz
margarine or vegetable fat
about 100 g (7 Tbsp)
-
CHOCOLATE SPONGE: Whisk together the flour, baking powder, and cocoa powder in a bowl. Set aside.
-
Cream the butter and sugar until light and fluffy. Add the egg yolks one at a time, beating after each addition, then beat in the milk.
-
Fold in the flour mixture just until combined — avoid overmixing to keep the sponge tender.
-
Pour the batter into a greased and floured 9×13″ (23×33 cm) pan. Bake in a preheated 350 F (175 C) oven for 18–20 minutes, until cooked through.
-
Combine the tea with the rum and pour the mixture over the hot cake so it soaks in and keeps the sponge moist.
-
MARSHMALLOW TOPPING: Beat the egg whites until stiff peaks form. Gradually add the sugar while continuing to beat.
-
Place the egg-white mixture over a double boiler and cook, stirring, for about 4–5 minutes. The mixture should become hot and glossy, but avoid overheating to prevent curdling.
-
Spread the warm marshmallow topping over the cake and smooth the surface with a spatula. Allow it to cool and set.
-
CHOCOLATE GLAZE: Melt the chocolate with the margarine or vegetable fat until smooth. Pour the glaze evenly over the cooled cake and let it set before serving.
Curious about marshmallows in unusual conditions? There are fun experiments online showing how marshmallows react in a vacuum.