To Make the Lemon Curd:

Combine all ingredients in a heavy, small-size saucepan and cook over medium-low heat, stirring constantly. Bring mixture just to the point where some bubbles rise and sauce has thickened, 6 to 8 minutes. Use a silicone spatula for stirring, and cook until sauce coats the spatula. When you draw your finger across the back of the spatula, the path should remain. Strain into small bowl and cover with plastic wrap. Cool to room temperature and refrigerate.

Heat oven to 425°F (220°C) with oven rack in middle.

To Make the Crust:

Place flour, sugar, and salt in a food processor bowl. Pulse about 5 times to mix. Add butter. Process until coarse crumbs form with some pea-sized pieces. Add 3 tablespoons (45 mL) ice water and process until dough begins to clump together. Process about 10 seconds. If large clumps do not form, add a little more water, 1 teaspoon at a time. Place dough on well-floured work surface and gather it together.

Divide dough into 8 pieces. Press each into bottoms of 8 (3-inch [7.5-cm]) tart pans. Press firmly against sides of pans. Pierce crusts generously with a fork.

Place tart shells on a baking sheet. Bake 12 minutes or until crusts are nicely browned. Cool to room temperature before filling. Gently release shells from the pans.

To Make the Filling:

Beat mascarpone cheese and whipping cream on low speed in bowl of a heavy-duty mixer fitted with the whisk until mixture begins to thicken. Scrape down sides of bowl. Increase mixer to high speed and beat until soft peaks form. Reduce mixer speed to medium.

Add powdered sugar and beat until mixed. By hand, stir in lemon curd. There can still be some streaks remaining. Divide the lemon cream into the tart shells.

Garnish with fresh fruit and refrigerate. Tarts can be made 4 hours ahead.