Step 1

Preheat oven to 160°C. Grease two 20cm (8-inch) round cake pans; line bases and sides with baking paper.

Step 2

Place poppy seeds and milk in a small bowl; soak 15 minutes.

Step 3

Beat butter and sugar in a medium bowl with an electric mixer for 6 minutes or until pale and fluffy. Beat in eggs, one at a time, until just combined. Add flour, ground hazelnuts, sour cream, and poppy seed mixture; beat on low speed until just combined. Spoon mixture evenly between pans.

Step 4

Bake cakes for 1 1/4 hours, swapping pans from top to bottom halfway during cooking time, or until a skewer inserted into the centre comes out clean. Stand cakes in pans for 5 minutes before turning, top-side up, onto baking-paper-covered wire racks to cool.

Step 5

Beat mascarpone, 1/2 cup of the cream and sifted icing sugar in a medium bowl with an electric mixer until firm peaks form.

Step 6

Place chocolate and remaining cream in a small saucepan; stir over low heat until melted and smooth. Cool for 5 minutes.

Step 7

Level cakes; split each cake into two layers. Reserve 60g raspberries for top. Place one cake layer on a cake stand; spread with one-third of the mascarpone mixture, then top with one-third of the remaining raspberries, squeezing them lightly to flatten. Repeat layering with remaining cake layers, mascarpone mixture and raspberries, finishing with a cake layer.

Step 8

Spread top of cake with chocolate mixture, allowing some to drizzle down the side. Decorate with reserved raspberries.