Preheat oven to 425F degrees. Spray a donut pan with nonstick cooking spray. Set aside.
In a large bowl, whisk together the flour, baking powder, baking soda, nutmeg, salt, and sugar. Set aside.
In a medium-sized bowl, whisk together the milk, sour cream, and eggs until smooth.
Whisk in the melted butter, vegetable oil, and vanilla extract. Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix. The batter will be very thick.
Spoon the batter into a large zipped bag. Cut a corner off the bottom of the bag and pipe the batter into each donut cup, filling 3 ∕ 4 of the way full.
Bake for 10 minutes or until the edges are lightly browned. Remove from the pan and bake the remaining donut batter. Allow the donuts to slightly cool before glazing.
MAKE THE VANILLA GLAZE:
In a medium-sized bowl, whisk together the milk, powdered sugar, and vanilla extract until smooth. Dip the top of each donut into the bowl of glaze, and sprinkle with colored sprinkles immediately after glazing. Let glaze set for 5-10 minutes before serving.
Notes
Use a large zip lock bag to fill the donut pan. It’s the easiest way! All you need to do is fill the donut batter into the ziplock bag and cut the corner off of one end and pipe the batter into each donut cup. Easy peasy.
Dipping the donuts. To make a thick glaze on top of these donuts, I like to dip each donut three times into the bowl of vanilla glaze. Let them set slightly after each dip until the last one when it's time to add the SPRINKLES.
Cool the donuts completely before adding the glaze. That way it will not melt off the donuts.
Different sprinkles. You can easily swap out the sprinkles for chocolate, single colored, round or whatever you prefer.
Store. Leftover baked donuts in an airtight container at room temperature for up to two days. You can refrigerate but the moisture in the fridge does cause the icing to weep a bit making the donuts a bit wet. You can freeze unglazed donuts for up to three months but I don't recommend freezing them if they are already glazed.