In a saucepan, pour the milk and add the lemon zest. Bring to a gentle boil, then remove from heat and let infuse.

In a bowl, whisk together the eggs, sugar, cornstarch, and lemon juice until smooth.

Slowly pour the warm milk into the egg mixture while whisking continuously. Return the combined mixture to the saucepan and cook over medium heat until thickened.

Remove from heat, then add the butter and optional yellow food coloring. Stir until fully combined and smooth. Cover to cool.

In a bowl, combine the flour, sugar, baking powder, and optional lemon zest. Using your fingertips, rub in the butter until the mixture resembles sandy crumbs.

Mix in the egg and knead until a soft dough forms.

Wrap the dough in plastic wrap and refrigerate for 30 minutes.

Butter the tartlet molds and press the dough into them, reserving some for decoration.

Refrigerate the filled molds for another 30 minutes.

Whisk the cooled lemon cream until smooth and fill the tartlet shells. Optionally, top with flaked almonds or pieces of reserved dough.

Preheat your oven to 180°C and bake the tartlets for 20-25 minutes until golden.

Let the tartlets cool slightly before unmolding them. Just before serving, dust with icing sugar for a beautiful presentation.