Step 1: Preheat and Prepare :Preheat your oven to 350°F (175°C). Lightly grease a donut pan with butter or nonstick spray.
Step 2: Mix Dry Ingredients : In a large bowl, whisk together flour, baking powder, baking soda, salt, and sugar until well combined.
Step 3: Combine Wet Ingredients ; In a separate bowl, whisk together buttermilk, eggs, melted butter, and vanilla extract until smooth and creamy.
Step 4: Combine and Mix : Pour the wet ingredients into the dry mixture. Stir gently with a spatula until just combined — do not overmix, as this can make the donuts dense.
Step 5: Fill the Donut Pan :Spoon or pipe the batter into the prepared donut pan, filling each cavity about ¾ full.
Step 6: Bake :Bake for 10–12 minutes, or until the donuts spring back lightly when touched and a toothpick inserted comes out clean.
Step 7: Cool : Let the donuts cool in the pan for 5 minutes, then carefully transfer them to a wire rack to cool completely before glazing.
Step 8: Make the Glaze : In a small bowl, whisk together powdered sugar, milk, and vanilla until smooth. Add a little more milk if you prefer a thinner glaze.
Step 9: Glaze and Decorate : Dip each cooled donut halfway into the glaze, let the excess drip off, and place it back on the rack. While the glaze is still wet, sprinkle with colorful sprinkles.