Prepare the gluten-free sweet pastry dough by following the recipe instructions.

Roll the chilled dough out to about 2 mm thick between two sheets of parchment paper, using a rolling pin.

Cut out rounds with a cookie cutter, then place them over an upside-down mini muffin tin.

Gently press the dough rounds over an upside-down mini tartlet pan, then freeze for 10 minutes.

Bake at 175°C for 12-15 minutes, until the pastry is golden.

Whisk the lemon juice, zest, cornstarch, eggs, and sugar together in a mixing bowl. Cook over a double boiler, whisking constantly, until thickened. Remove from the heat.

Blend in the cold vegan butter with an immersion blender, or whisk until smooth.

Fill the tartlet shells with lemon curd, then refrigerate until set.

In a small saucepan, bring the water and sugar to a boil. Meanwhile, begin whipping the egg whites with a hand mixer or stand mixer until partially whipped.

When the sugar syrup reaches 120°C, remove it from the heat and slowly pour it into the partially whipped egg whites in a steady stream.

Increase the mixer to high speed and keep whisking until the meringue is firm, glossy, and cool. Use immediately.

Pipe the meringue onto the filled tartlet shells, then toast it with a kitchen torch. Skip this step if you do not have one.