Step 1

For the tarts: Preheat the oven to 425 degrees F. Line 2 sheet pans with parchment paper.

Step 2

On a lightly floured work surface, lay out the puff pastry. Cut the puff pastry sheets in half, making 4 rectangles. Place 2 puff pastry rectangles on each sheet pan. Set aside.

Step 3

Add the blueberries and strawberries to separate bowls. Divide the granulated sugar, cornstarch and lemon juice between the bowls. Season each with a pinch of salt and stir until well combined.

Step 4

Divide the blueberries between 2 of the puff pastry rectangles, leaving a 1/4-inch border on all sides. Do the same with the strawberries and the remaining puff pastry rectangles. Pinch the corners of each rectangle, creating a slight lip. Brush the edges with the cream.

Step 5

Bake in the lower half of the oven until golden and crisp, about 20 minutes.

Step 6

For the whipped cream: While the tarts bake, add the cream, powdered sugar and vanilla to a large bowl. Using a hand mixer or whisk, whip until soft and billowy. Transfer to a serving bowl and chill until ready to serve.

Step 7

Transfer the tarts to a cutting board. Let the tarts cool slightly before slicing approximately 6 times across each tart to create thin slices. Transfer to a serving platter. Scatter the mint leaves over the tart pieces and sprinkle with powdered sugar. Serve alongside the whipped cream.