Line a 2-quart bowl entirely with plastic wrap, leaving a generous overhang.

Brush pound cake slices lightly with warmed jam. Line the inside of the bowl tightly with the cake slices, jam-side facing in.

Whip the heavy cream, mascarpone, powdered sugar, and vanilla until stiff peaks form.

Fold diced strawberries into 1/3 of the whipped cream. Fill the cake-lined bowl halfway with this mix. Add a layer of plain cream on top, leaving 1/2 inch of space. Reserve remaining cream.

Cover the top with remaining cake slices. Fold the plastic wrap over to seal. Refrigerate for at least 6 hours or overnight.

For the glaze: Simmer 2 cups strawberries, sugar, and lemon juice until soft. Blend and strain to remove seeds. Return to heat.

Whisk cornstarch and cold water into a slurry, add to the boiling strawberry juice, and cook until thick and glossy. Let cool completely.

Unmold the chilled cake onto a plate and remove the plastic wrap.

Arrange the large strawberries around the dome. Pipe thick swirls of the reserved whipped cream between the berries.

Right before serving, generously pour the cooled, thick glossy strawberry glaze over the cake, allowing it to pool on the plate.