1-Prepare your workspace by sifting 105 grams powdered sugar, 105 grams almond flour, and 5 grams cornstarch with the vanilla bean seeds.

2-Whisk 100 grams egg whites and 100 grams granulated sugar over heat until frothy, then beat to stiff peaks for the meringue.

3-Fold the dry mixture into the meringue carefully, add optional food coloring if desired, and avoid overmixing.

4-Pipe the batter onto parchment-lined trays, tap to remove air bubbles, and allow to rest for 40 minutes.

5-Bake at 300°F (150°C) for 18 minutes, then cool the shells completely.

6-For the custard, heat 3/4 cup milk with seeds from 1/2 vanilla bean pod, whisk in 1 egg yolk, 2 tablespoons granulated sugar, and 1 tablespoon cornstarch until thickened, then cool.

7-Make the buttercream by creaming 4 tablespoons softened unsalted butter with seeds from 1/2 vanilla bean pod, then add 1 1/2 cups sifted confectioners sugar, 1/2 teaspoon vanilla extract, and 2 tablespoons milk until smooth.

8-Assemble by piping buttercream around the edges of half the shells, fill with cooled custard, and sandwich with another shell.