Classic French Macaron with Vanilla Buttercream Filling

INGREDIENTS

• 1/2 cup Aged Egg Whites (from 4 eggs, aged covered in the fridge for 1-2 days) - Room Temperature
• 1 Vanilla Bean
• pinches Salt
• 2 Sticks, cold unsalted butter, cubed
• 1 pinch Cream of Tartar
• 3/4 cups Granulated Sugar
• 1 cup Granulated Sugar
• 1 tablespoon Powdered Egg Whites
• 1/2 teaspoon Cream of Tartar
• 1/4 teaspoon Fine Sea Salt
• 3 Egg Whites
• 3/4 cups Confectioners' Sugar (packed)
• 4 drops Gel food color (optional)
• 1 1/4 cup Almond Flour (Blanched)
• 1 tablespoon Vanilla Extract