Chocolate Bomb With Chocolate Rum Mousse

Published on February 24, 2022

This recipe is over 40 years old, back in the days when we were making Caesar salad dressing using raw egg whites, and throwing whole raw eggs into our protein drinks in the mornings, not having to worry about salmonella poisoning. The high risk of salmonella poisoning has passed but to be on the safe side, I still didn’t want to post a recipe calling for raw egg whites that wouldn’t be cooked. If you are comfortable with and would prefer to use normal eggs whites, the original recipe for the mousse called for 5 egg whites.

If you can find a 3 quart bowl that is deep and very rounded looking, that is best. Pictured is Sur La Table’s 3 quart mixing bowl.

Chocolate Bomb With Chocolate Rum Mousse

Note: The size of eggs are not uniform in a carton of “large” eggs. Some can be more medium size, some large, and some more towards the size of extra large. Use the largest sized large eggs.

Brownie Cake Layer



Butter a large (around 12″ by 17″) baking sheet or jelly roll pan. Add a sheet of parchment (waxed paper does not work as well) and butter and flour it.

Gently melt chocolate with 2 tablespoons of the butter in a heavy bottomed pot over low heat. Cool slightly (if it gets too cold it will start to harden and won’t mix in smoothly).

Using the paddle attachment, cream remaining butter with sugar in a mixer. Add eggs one by one. Add vanilla, salt and chocolate mixture. Add the flour, a third at a time. So these steps scraping down the bowl as needed.

Spoon the batter on to the prepared baking sheet. Spread evenly in pan and bake 21 minutes in a 350° oven. Do not over bake. If you leave it in a few minutes too long, when you try to cut it, it will be very hard and the outside of the cake will break off into dry shards of cake.

The cake will be very thin, moist and flavorful.

Chocolate Rum Mousse Filling

I have listed pasteurized egg whites because in mousses the whites are not being cooked. If you want to use regular whites, it’s 5 large egg whites.



Gently melt both chocolates in a heavy bottomed pot over low heat.

Sprinkle gelatin over rum in a small bowl.

Make the custard: Place the yolks in a heavy saucepan and slowly whisk in the heavy cream. Place the pan on medium heat and cook until you see some steam rising and the mixture has thickened, whisking often. Whisk in the vanilla and the gelatin mixture, and then the melted chocolate.

Using the whisk attachment, whip the egg whites with the salt to soft peaks (about a minute), then add the 3 tablespoons of sugar and beat to stiff peaks (a couple more minutes). Gently fold into the chocolate mixture as best you can. It will end up more liquidy than expected.*

*Note: If you allow the mixture with the gelatin to become too cold, the gelatin will have started to set up and then when you disturb it as you fold in the whites, it would be like disturbing jello as it’s starting to set up. The texture would not be the same and it makes all the difference with this particular recipe.


Line a 3 quart bowl with plastic wrap. I put two long pieces side by side in the bowl, pushing them down and flush against the sides of the bowl one at a time.

Cut the brownie cake to fit the inside of the bowl. How you make your cake ‘puzzle’ pieces doesn’t matter. I begin with a 5″ round piece at the bottom and then pieces around the sides up to about 1 to 1 1/2 inches from the top of the bowl. Face the darker side of the cake pieces towards the bowl. Fill in any open spaces with small pieces of the cake. It doesn’t have to be perfectly neat because the glaze will be going over it.

Ladle half of the mousse into cake lined bowl and then place a layer of cake pieces on the mousse. Depending on what you want the outcome to look like, use larger pieces to make the inside look distressed when you cut into it or use small pieces to just have them blend in.

Ladle the other half of the mousse over the pieces. If the mousse doesn’t come up almost to the top of the sides of cake, trim the sides down to just above the cake. Then use large pieces of the cake for what is going to be the bottom of the bomb, filling in the cracks with little pieces and making it as flat and even as possible. It will be tricky having to work with the mousse being very liquidy but remember that it doesn’t have to be perfect to turn out great.

Fold the plastic wrap over the bottom to seal. Chill until the mousse overnight.

Final Glaze



Gently melt the chocolate in a heavy bottomed pot over low heat.

Loosen the cake from the bowl by briefly running warm water over the sides and bottom, and unmold the cake on to a cookie rack to catch drips. Spoon the glaze over the cake and quickly ice the whole cake with a knife. Transfer to the serving dish. Keep refrigerated.

To serve, cut into wedges and serve with whipped cream.