Recipe Detail Page

1. Line an 8-inch (20-cm) square baking pan with a cross of parchment paper so all four sides are lined. Arrange half the vanilla wafers in a single layer on the bottom of the pan. Fill in any gaps with broken pieces of wafer. Set the pan aside and reserve the remaining wafers.

2. For blackberry mousse, combine the blackberries and ¾ cup (175 mL) sugar in a saucepan and bring to a boil, stirring occasionally. Simmer for 5 to 10 minutes. Cool slightly then purée in a food processor. Strain through a fine mesh sieve and discard the seeds. Measure 1⅔ cups (400 mL) of the purée for finishing the mousse, and reserve the remaining purée in the refrigerator. (This will be used when layering the cake and when serving.)

3. Pour the cassis and lemon juice into a small bowl, add the gelatin and immediately stir with a fork to dissolve the gelatin.

4. From the 1⅔ cups (400 mL) of purée, pour about half into a small saucepan and bring to a simmer. Add the gelatin mixture and whisk until completely dissolved. Add the hot purée to the remaining purée and whisk to combine. Chill the mixture over a bowl of ice water until no longer warm to the touch and just starting to thicken.

5. Combine 1¾ cups (425 mL) whipping cream, sour cream and 2 tbsp (30 mL) sugar in the bowl of an electric mixer fitted with the whisk attachment. Whip to soft peaks then fold into the blackberry mixture.

6. Pour half the mousse into the prepared pan and level the surface. Top with the fresh raspberries, pushing them lightly into the mousse. Place another layer of vanilla wafers over the raspberries and, again, fill in the gaps with broken pieces of wafer. Drizzle about ¼ cup (60 mL) of the chilled blackberry purée over the wafers. Transfer the remaining mousse overtop and smooth the surface. Tap the pan on the work surface one or two times to remove any air pockets. Cover the surface with plastic wrap and refrigerate overnight.

7. To remove, turn the cake pan upside down onto a plate or cake rack. Remove the pan and parchment paper, then flip the cake back over onto a serving plate. Remove the plastic wrap from the top surface.

8. For topping, place 1 cup (150 mL) whipping cream and remaining 2 tbsp (30 mL) sugar in the bowl of an electric mixer fitted with the whisk attachment. Whip to stiff peaks and transfer to a piping bag with a decorative tip. Pipe the cream over the top of the cake and decorate with fresh berries. Serve with the reserved blackberry purée and some extra berries and mint leaves on the plate.