01 - Preheat oven to 350°F. Generously grease two 6-cavity donut pans with butter or nonstick spray.
02 - In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt until evenly distributed.
03 - In a separate bowl, whisk together the whole milk, eggs, melted butter, and vanilla extract until smooth.
04 - Pour the wet ingredients into the dry ingredients and fold gently with a spatula until just combined. Be careful not to overmix, as this can make the donuts tough.
05 - Spoon the batter into the prepared donut pans, filling each cavity approximately three-quarters full. Smooth the tops if needed.
06 - Bake for 10 to 12 minutes, or until a toothpick inserted into the center comes out clean and the donuts spring back lightly when touched.
07 - Allow the donuts to rest in the pans for 5 minutes, then carefully transfer them to a wire cooling rack. Let them cool completely before frosting.
08 - In a mixing bowl, beat the room-temperature butter with an electric mixer until creamy and pale. Gradually add the sifted powdered sugar, beating on medium speed until light and fluffy.
09 - Add the strawberry puree, vanilla extract, and a pinch of salt to the buttercream. Beat for 2 to 3 minutes until the frosting is smooth, light, and evenly pink.
10 - Once the donuts are completely cool, spread or pipe the strawberry buttercream generously over each one. Top with thinly sliced fresh strawberries or sprinkles as desired.