Preheat and prep. Heat your oven to 350°F (175°C). Lightly grease a standard doughnut pan with oil spray. If using silicone, place it on a sheet pan for stability.
Mix dry ingredients. In a large bowl, whisk 2 cups all-purpose flour, 3/4 cup granulated sugar, 2 tsp baking powder, 1/2 tsp fine salt, and 1/4 tsp ground nutmeg (optional) until combined.
Combine wet ingredients. In a separate bowl, whisk 2 large eggs, 1/2 cup milk, 1/2 cup sour cream or yogurt, 1/4 cup melted unsalted butter (cooled slightly), and 1 tsp vanilla extract until smooth.
Make the batter. Pour the wet ingredients into the dry. Stir with a spatula just until no dry spots remain. The batter will be thick but spoonable. Avoid overmixing to keep the texture tender.
Fill the pan. Transfer the batter to a piping bag or a zip-top bag with a corner snipped. Pipe into the doughnut wells, filling each about 3/4 full. Smooth tops if needed.
Bake. Bake for 10–12 minutes, until the doughnuts spring back lightly to the touch and a toothpick comes out clean. Edges should be just turning golden.
Cool. Let them rest in the pan for 5 minutes, then gently turn onto a wire rack. Cool another 10 minutes before glazing.
Make the chocolate glaze. In a medium bowl, whisk 1 1/2 cups powdered sugar, 1/4 cup unsweetened cocoa powder, a pinch of salt, 1 tsp vanilla, and 3–4 tbsp milk until smooth and glossy. For extra shine and softness, whisk in 1 tbsp melted butter.
Adjust consistency. The glaze should flow slowly off the whisk and leave a smooth coating. If too thick, add milk 1 tsp at a time. If too thin, add a bit more powdered sugar.
Dip and set. Dip the top of each cooled doughnut into the glaze, let excess drip, then place back on the rack. Add sprinkles while the glaze is still wet. Let set for 15–20 minutes.
Serve. Enjoy slightly warm or at room temperature. The glaze will firm up but stay soft to the bite.
Air-fryer option. Pipe batter into silicone doughnut molds that fit your air fryer. Cook at 325°F (165°C) for 7–9 minutes, checking at 7 minutes. Cool and glaze as above.
