Guinness, Whiskey and Irish Cream Cake

STEP 1: PREPARE THE PANS

Heat the oven to 325°F. Grease three 8-inch round cake pans with butter and line the bases with parchment paper. Three shallow layers bake and cool faster than two deep ones.

STEP 2: MAKE THE STOUT BASE

Warm the Guinness and cubed butter in a large saucepan over low heat until the butter melts. Take off the heat and whisk in the cocoa powder and sugar.

STEP 3: ADD THE WET INGREDIENTS

Whisk the mayonnaise, eggs and vanilla extract together until smooth, then whisk into the stout mixture.

STEP 4: ADD THE DRY INGREDIENTS

Sift the flour, baking soda, baking powder and salt together twice through a fine sieve. Whisk into the wet mixture until just smooth. The batter will be thin.

STEP 5: BAKE THE SPONGES

Divide the batter equally among the pans. Bake for 28–32 minutes, until the center reads 200–205°F on an instant-read thermometer or a skewer comes out with a few moist crumbs. Keep the oven low; do not raise the heat to save time.

STEP 6: MAKE THE WHISKEY GANACHE

While the sponges bake, bring the heavy cream just to a simmer and pour it over the chopped chocolate in a heatproof bowl. Rest for 2 minutes, then stir from the center out until smooth. Stir in the whiskey and salt. Leave at room temperature, stirring now and then, until thick and spreadable, about 70°F.

STEP 7: COOL AND CHILL THE SPONGES

Cool the sponges in their pans for 10 minutes, then turn out onto wire racks and cool for 30 minutes. Chill the layers, uncovered, for 20 minutes. Check with the thermometer: the center must read 75°F or below before any filling goes on.

STEP 8: HEAT THE MERINGUE

While the sponges cool, whisk the egg whites and sugar in a heatproof bowl set over simmering water until the sugar dissolves and the mixture reaches 160°F.

STEP 9: WHIP THE MERINGUE

Transfer to the stand mixer fitted with the whisk and whip on high speed until a stiff, glossy meringue forms and the bowl feels cool, 8–10 minutes.

STEP 10: ADD THE BUTTER

Switch to the paddle attachment. Add the butter a few cubes at a time on medium speed. If the mixture looks curdled, keep beating; it will come together.

STEP 11: FLAVOR THE BUTTERCREAM

Beat in the vanilla extract and salt, then the Irish cream a tablespoon at a time. Check the temperature: 68–72°F is right for piping. If it is too soft, chill the bowl for 5 minutes and re-beat; if it is too firm, warm the sides of the bowl briefly and re-beat.

STEP 12: FILL THE CAKE

Level the chilled sponges if domed. Set the first on a cake board on the turntable. Pipe a ring of buttercream around the edge as a dam, then spread half the set ganache inside it. Add the second sponge and repeat with the remaining ganache. Top with the third sponge, base side up.

STEP 13: CRUMB COAT AND CHILL

Cover the cake in a thin crumb coat of buttercream using an offset spatula. Chill for 20 minutes, until firm to the touch.

STEP 14: APPLY THE FINAL COAT

Apply a smooth final coat of buttercream, finishing with the bench scraper. Chill for 15 minutes more. Keep the remaining buttercream at 68–72°F.

STEP 15: PIPE THE SCALLOPED BAND

Fit a piping bag with the tip and fill it only half full. Pipe a band of scallops around the middle of the chilled cake. Swap to a fresh bag if the buttercream softens, and if the cake starts to feel soft, stop and chill it for 5 minutes before carrying on.

STEP 16: SERVE

Hold the cake at cool room temperature until serving and slice with a hot, dry knife. The sponges keep for one day well wrapped; the buttercream keeps for three days refrigerated. Bring it to cool room temperature and re-beat before use.