Vanilla Chocolate Heart Mousse Cake Recipe

Prepare and bake

Preheat oven to 350°F (175°C). Line and lightly grease a 9-inch (23 cm) round cake pan or springform. In a medium bowl whisk together flour, cocoa powder, baking powder, and salt until evenly combined.

In a separate large bowl whisk eggs and sugar until pale and slightly thickened, about 2–3 minutes by hand or 1 minute with a mixer. Whisk in vegetable oil, milk and vanilla extract until smooth.

Gently fold dry ingredients into wet mixture until just combined; avoid overmixing. Pour batter into prepared pan and smooth the top.

Bake 12–18 minutes until a toothpick inserted into the center comes out with a few moist crumbs. Let cool in pan 10 minutes, then transfer to a wire rack to cool completely. Once cooled, trim or level the sponge so it will fit the cake ring/mold you’ll use (approx 8–9 inch ring).

Bloom gelatin

Sprinkle 1.5 tsp gelatin over 30 ml cold water in a small bowl. Let sit 5–7 minutes to bloom.

In a small saucepan warm 200 ml milk with 40 g sugar and vanilla bean paste over medium heat until hot but not boiling and sugar is dissolved. Remove from heat and whisk in bloomed gelatin until fully dissolved. Let mixture cool to room temperature (10–15 minutes), stirring occasionally.

While milk mixture cools, whip 300 ml chilled heavy cream to soft peaks. Fold about one third of the whipped cream into the cooled milk/gelatin mixture to lighten, then fold in remaining cream gently until fully combined and smooth.

Transfer vanilla mousse to a heart-shaped silicone mold or a small heart-shaped insert placed inside your main cake ring. Smooth the top and freeze for at least 2 hours (or up to overnight) until firm. This will be demolded and inserted into the chocolate mousse later.

Bloom gelatin

Sprinkle 1.5 tsp gelatin over 30 ml cold water in a small bowl. Let sit 5–7 minutes.

Place 200 g chopped semi-sweet chocolate in a heatproof bowl. Heat 60 ml hot water with 1 tsp espresso (if using) and pour over chocolate. Let sit 1 minute, then whisk until smooth and glossy. If needed, microwave in 10-second bursts to fully melt and smooth.

Warm the bloomed gelatin briefly (10–15 seconds) in the microwave or over a double boiler just until melted, then whisk it into the melted chocolate mixture until fully incorporated. Let chocolate mixture cool to around 30–35°C (warm but not hot).

Whip 400 ml chilled heavy cream to soft peaks. Fold one quarter of the whipped cream into the chocolate base to loosen, then gently fold in the remainder until a smooth, homogeneous mousse forms. Keep the mousse chilled but pourable.

Assemble: place the trimmed chocolate sponge into an 8–9 inch cake ring or springform with a removable base lined with acetate for smooth sides. Pour a layer of chocolate mousse (about one-third of the total) to create a base, smoothing level. Place the frozen vanilla heart mousse in the center (flat side down). Pour remaining chocolate mousse around and over the vanilla heart, ensuring it is fully enclosed and the top is smooth. Tap gently to remove air bubbles.

Refrigerate the assembled cake 4 hours to set (or freeze 1–2 hours for quicker set). If frozen, allow to thaw in refrigerator 2–3 hours before glazing.

Make glaze

Place 120 g chopped dark chocolate in a bowl. Heat 120 ml heavy cream until it just begins to simmer. Pour hot cream over chocolate, let sit 1 minute, then whisk until smooth. Add 20 g butter and whisk until glossy and combined. If glaze is too thick, warm gently; if too thin, let cool a bit to thicken to pouring consistency.

When cake is fully set and cold (chilled or slightly firm from freeze but not rock solid), remove ring and acetate. Place cake on a wire rack over a tray. Pour glaze gently over the top, starting in the center and letting it run to the edges to coat smoothly. Use an offset spatula to help if needed. Let excess drain away.

Transfer cake to serving plate once glaze sets (about 15–20 minutes). Decorate with chocolate shavings or curls and dust a light sprinkle of cocoa powder if desired. Chill at least 30 minutes before serving to allow mousse to settle.