Preheat the oven to 425 (F). Prepare your donut pan by spraying each donut cavity liberally with cooking spray; set aside.
In a medium bowl, combine 2 cups all-purpose flour, 3/4 cup granulated sugar, 2 teaspoons baking powder and 1 teaspoon ground vanilla bean powder and whisk until thoroughly combined.
In a large bowl, whisk together 3/4 cup buttermilk, 1 teaspoon pure vanilla extract, 2 large eggs and 2 tablespoons melted unsalted butter until thoroughly combined.
Sprinkle the dry ingredients (from the 2nd step) over the surface of the wet ingredients (from the 3rd step) and use a rubber spatula to fold the dry ingredients into the wet ingredients until fully incorporated. Transfer the batter to a pastry piping bag and fill each donut cavity until it is approximately 1/2 full. Bake in the preheated oven for 8 to 10 minutes, or until the top of the donuts spring back when gently poked with your finger. Use a butter knife or a mini offset spatula to flip the donuts on their pan so that the exposed part is now touching the pan. Allow to cool in the pan on a wire rack for 4 to 5 minutes, before transferring to the pan to cool completely. Glaze the donuts when they reach room temperature.