For the doughnuts:
- 1/3 cup plus 1 tablespoon buttermilk
- 1 tablespoon unsalted butter, melted and cooled slightly
- 1 egg
- 1 cup cake flour, sifted
- 1/3 cup plus 1 tablespoon granulated sugar
- 1 teaspoon baking powder
- 1/2 teaspoon salt
- Seeds from 1/2 vanilla bean
For the glaze:
- 1 cup powdered sugar
- 3 tablespoons finely chopped strawberries
- Red gel food coloring (optional)
- Sprinkles, for topping (optional)
- Heat oven to 400 degrees F (375 for a dark or nonstick doughnut pan). Lightly grease a 6-cavity doughnut pan.
- In a large bowl, whisk together buttermilk, melted butter and egg until combined. In a separate medium bowl, whisk together cake flour, sugar, baking powder, salt and vanilla bean seeds.
- Add dry ingredients to wet ingredients: stir to combine. Divide batter evenly in doughnut pan.
- Bake 8 to 12 minutes until doughnuts are baked through and spring back when lightly pressed. Cool 1 minute in pan, then transfer to a cooling rack to cool completely before glazing.
- Make the glaze just before you plan to dip the doughnuts. In a medium bowl, stir together half the powdered sugar and all of the chopped strawberries until well combined. Let sit 1 minute, then add remaining powdered sugar and stir until a glaze forms. Dye with a drop of red food coloring, if desired.
- Dip doughnuts one at a time into glaze. Top with sprinkles, if desired. Let glaze set completely before serving.