Preheat the oven to 350˚F. Spray two 12-cup mini muffin pans (or one 24-cup mini muffin pan) with baking spray. Rub each cup with a piece of paper toweling to make sure they're thoroughly coated, including the top edges.

Place the soft butter and powdered sugar in a medium-size bowl and stir until smooth and creamy. Add the vanilla and stir to combine. Sprinkle in the corn starch and stir until nice and smooth.

Add the flour and salt and stir, turning the bowl with and stirring from the bottom up. At first the dough will be very shaggy and dry, but after a minute or so it will come together nicely. Just keep stirring until all of the flour is incorporated and the dough comes together in a big clump.

Divide the dough into 24 equal portions. You can eyeball this or use a digital scale. I weigh the dough then divide by 24. It usually comes out to 25-26g each. Give each portion of dough a little squeeze and hold it in your hand for about 10 seconds (to compress and warm the dough a bit) then roll it between your palms into round balls.

Place each ball into one of the prepared mini muffin cups and flatten each one gently with your fingers. Using a ½ teaspoon measuring spoon, make an indention in the center of each flattened ball.

Place the pan(s) in the preheated oven and bake for 18-24 minutes or until the outer edges of each tart are a medium golden brown.

Remove the pan(s) from the oven and immediately reinforce the center wells by gently pushing in again with the ½ teaspoon measuring spoon.

Allow the tart shells to cool in the pan for 10 minutes then remove by inserting a small sharp knife into the center of each shell and pulling upward. Cool completely on a cooling rack before filling.

Using a spoon fill each well with 1-1 ½ teaspoons of lemon curd. Garnish with a mint sprig or a small edible flower, if desired.