01 - Preheat oven to 350°F. Grease two 6-cavity donut pans and set aside.
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, room-temperature eggs, melted unsalted butter, and vanilla extract until smooth.
04 - Pour the wet mixture into the dry ingredients and fold gently with a spatula until just combined. Avoid overmixing to keep the donuts light and tender.
05 - Spoon the batter into the prepared donut pans, filling each cavity approximately three-quarters full.
06 - Bake for 10 to 12 minutes, or until a toothpick inserted into the center comes out clean and the donuts spring back when lightly touched.
07 - Allow the donuts to cool in the pans for 5 minutes, then transfer them to a wire cooling rack to cool completely before frosting.
08 - Using an electric mixer, beat the room-temperature unsalted butter on medium speed until creamy and pale, approximately 2 minutes.
09 - Gradually add the sifted powdered sugar, beating continuously until light and fluffy. Then incorporate the strawberry puree, vanilla extract, and a pinch of salt. Beat for an additional 2 to 3 minutes until the frosting is smooth and spreadable.
10 - Once the donuts are completely cool, spread or pipe the strawberry buttercream generously over the top of each donut.
11 - Finish with thinly sliced fresh strawberries or sprinkles as desired. Serve immediately or store in an airtight container.