In a heat-safe bowl, whisk together granulated sugar and eggs until smooth. Add the zest and juice of three large lemons along with the melted butter. Place the bowl over a double boiler or microwave it for 4-5 minutes, stirring continuously, until the mixture thickens and coats the back of a spoon.

Preheat your oven to 375°F (190°C) while you prepare your tart shells. Grease a mini muffin tin with cooking spray. Roll out the pie crust and use a flower-shaped cookie cutter to cut out pieces. Gently press the dough into each muffin tin cup.

Bake the tart shells for 8-10 minutes, or until golden brown. Once baked, let them cool in the pan for about 5 minutes before moving to a wire rack.

Once the lemon curd and tart shells are cooled, fill each shell with the lemon curd, generously without overflowing.

Dust lightly with powdered sugar before serving. Serve chilled or at room temperature.