Foryoueats: Alfajores Con Cajeta (Vanilla Shortbread With Goat's-Milk Toffee) Recipe

Ingredients

• 1 vanilla bean, preferably Mexican
• 4 ounces all-purpose flour (3/4 cup plus 1 tablespoon; 115g)
• 3 ounces tapioca starch (3/4 cup; 85g)
• 2 ounces powdered sugar (1/2 cup; 55g), plus more for dusting
• 1/4 teaspoon (1g) Diamond Crystal kosher salt
• 1/4 teaspoon (1g) baking powder
• 4 ounces cold unsalted butter (1 stick; 115g), cut into 1/4-inch pieces
• 2 large egg yolks, cold
• 1 recipe Cajeta Casera (see note)