Equipment

• 9 inch springform pan, parchment for the base
• Acetate cake collar or a parchment strip 28 inches long by 3 inches tall
• 2 mixing bowls, small saucepan, small pot for glaze
• Hand mixer or stand mixer for whipped cream
• Instant-read thermometer for the glaze (optional but helps)
• Fine mesh strainer for glaze
• Offset spatula and a long sharp knife warmed in hot water for slicing

Ingredients (cups and tablespoons only)

Step-by-step Method

1. Set up the pan. Heat oven to 350 F. Line the springform base with parchment. Grease the sides lightly. If you own an acetate collar, cut it to fit and set aside for later.
2. Mix the fudgy base. In a bowl whisk butter and sugar until combined and slightly lightened, about 60 seconds by hand. Beat in eggs and vanilla until smooth. In another bowl whisk cocoa, flour, baking powder, and salt. Stir the dry mix into the wet until almost combined, then stir in hot coffee. Batter will loosen and turn glossy. Spread evenly in the pan.
3. Bake. Bake 18 to 22 minutes. Look for a few moist crumbs on a toothpick. The top should look set and slightly shiny. Cool 10 minutes on a rack. Run a knife around the edge to release but keep the cake in the pan.
4. Seal with ganache. Heat cream to steaming. Pour over chocolate and salt. Wait 1 minute, then whisk smooth. Spread a thin layer over the cooled cake. You want an even coat, not a thick slab. Chill 10 minutes to set the surface.
5. Layer the raspberry gel. Sprinkle gelatin over 2 tbsp cold water and let it bloom 5 minutes. Warm jam and lemon in a small pan until it just bubbles at the edge. Off heat, whisk in gelatin until fully melted. Cool 10 minutes. Pour or spread a thin layer over the ganache. Chill 20 minutes until jiggly and set.
6. Build a tall ring. Wrap the inside wall with an acetate collar or a parchment strip that rises at least 2 inches above the pan. Clamp the pan closed so the collar stays in place. This holds the taller mousse layer.
7. Cook the raspberry base for the mousse. Sprinkle gelatin over 3 tbsp cold water; stand 5 minutes. In a saucepan combine raspberry puree, sugar, and lemon. Heat over medium until hot and the sugar dissolves, about 2 to 3 minutes; do not boil hard. Remove from heat. Whisk in the bloomed gelatin until melted. Cool to room temp, stirring every few minutes so the edges do not set.
8. Whip cream and fold. Beat cream and vanilla to soft peaks. Do not overwhip or the mousse turns grainy. Fold one third of the whipped cream into the raspberry base, then fold in the rest until smooth and uniform.
9. Fill and set. Pour mousse over the gel. Tap the pan on the counter to knock out air bubbles and level the top with an offset spatula. Chill at least 3 hours, or freeze about 60 to 75 minutes, until fully set and the top is firm to the touch.
10. Make the shiny glaze. Bloom gelatin in 2 tbsp cold water. In a small pot whisk sugar, cocoa, and salt. Add water, cream, and corn syrup. Bring to a gentle boil over medium heat, whisking. Simmer 2 minutes to dissolve the sugar. Remove from heat and whisk in the gelatin. Strain into a pitcher. Cool to 90 to 95 F. If you do not have a thermometer, dip a spoon: the glaze should feel warm but not hot and coat the back of the spoon in a thin film.
11. Unmold and glaze. Run a hot knife around the inside edge. Release the springform and peel off the acetate. Set the chilled cake on a rack over a tray. Pour glaze in one steady motion over the center, letting it run to the edges and down the sides. Do not scrape or re-pass; it will self level. Slide onto a platter and chill 20 minutes to set.
12. Finish and slice. Pile fresh raspberries on top. Wipe a long knife in hot water, dry it, and cut clean slices, reheating and wiping between cuts.

Timeline: cake and gel take about 45 minutes including cooling time. Mousse sets 3 hours. Glaze is a 10 minute cook plus cool to temperature. Realistic start-to-serve is about 5 hours with chilling.

Substitutions and Variations

Troubleshooting

• Glaze shows streaks or bare spots: It was too hot or the cake was not cold enough. Chill the cake harder next time. If it happened already, let the glaze firm and do a single, thin second pour at 92 F.
• Mousse looks grainy: The cream was whipped too stiff or the raspberry base was still warm and shocked the cream. Whip to soft peaks only and cool the base to room temp before folding.
• Gel slid when slicing: You poured a very thick glaze or sliced with a dull knife. Heat the knife, wipe between cuts, and slice with confidence in one motion.
• Cake layer crumbles into the mousse: You skipped the ganache seal or spread it too thin. Do not skip it; it is the crumb lock.
• Glaze dull, not shiny: It crystallized. Make sure sugar fully dissolves and strain the glaze. Do not scrape the pot sides into the pitcher.

FAQ

Can I use frozen raspberries?

Yes. Thaw, then puree and strain. Frozen fruit is often more consistent, which is why bakeries use it. Do not add extra water beyond the small amount in the recipe.

Can I skip the gel layer?

You can, but you will lose that sharp fruit punch and the flavor will be rounder and sweeter. If you skip it, increase the lemon in the mousse by 1 tsp and bump puree to 1 1/2 cups so the fruit stands up to the chocolate.

How do I get a perfectly level top?

Tap the pan a few times on the counter after you pour the mousse, then smooth gently with an offset spatula. If you see a bubble on top of the chilled mousse, pop it with a toothpick before glazing.

What chocolate works best for the glaze?

This glaze is cocoa-based, not chocolate-based, so it will always be shiny and thin enough to self level. If you want a thicker, darker look, whisk in 1/4 cup chopped dark chocolate after the simmer and melt it off heat.

How do I clean up the base of the cake after glazing?

Lift the rack, scrape excess glaze from the tray back into a container, then slide the cake to a clean board and wipe the bottom edge with a warm, damp towel.