5 large egg whites (6 ounces/180 grams) at room temperature

3/4 cup whole milk (180 mL/6 liquid ounces), at room temperature

2 1/4 teaspoons pure vanilla extract (9 grams) — I use Nielsen-Massey Vanillas 8-oz. Madagascar Bourbon Vanilla Extract

2 1/2 cups sifted cake flour (8.5 ounces/250 grams)

1 3/4 cups sugar (12 ounces/350 grams)

1 tablespoon + 1 teaspoon baking powder (19.5 grams)

3/4 teaspoon salt (5 grams)

12 tablespoons unsalted butter (6 ounces/170 grams), at room temperature and cut into cubes