Step 1

In a medium bowl, combine the berries, jam and a pinch of salt. Gently toss, then let stand at room temperature until the berries soften and release juices, about 30 minutes, or cover and refrigerate up to 12 hours. Meanwhile, in a large bowl and using a silicone spatula, stir the mascarpone to soften. Stir in the sugar. Whisk in the cream and vanilla until it holds soft peaks; do not overwhip. Cover and refrigerate until ready to use or up to 12 hours.

Step 2

Set 1 of the cakes on a platter. Spoon on half of the berry mixture, leaving a 1-inch border at the edge. If the mascarpone cream has been refrigerated for more than a couple of hours, give it a stir to re-soften. Dollop half of the mascarpone cream over the berries then, using the back of a large spoon, spread evenly, leaving a 1-inch border at the edge.

Step 3

Place the second cake on top. Scoop the remaining cream onto the center of the cake. Using the back of the spoon, spread the cream, leaving a 1-inch border at the edge and creating swooshes, swirls and a shallow well in the center. Spoon the remaining berry mixture into the center and drizzle with the juices remaining in the bowl. Serve right away.