In another bowl, beat the vanilla, egg, sour cream, milk, and oil until well incorporated. Add the wet ingredients to the bowl of dry ingredients. Stir only until combined.
Spoon the batter (or pipe it) into a greased doughnut pan. Fill each "well" about 3/4 of the way full with batter. Bake doughnuts at 375 degrees for 8 minutes, or until the top of the doughnut springs back when touched.
Remove doughnut pan from oven when done, and let the doughnuts cool IN THE PAN for 2-3 minutes before you remove them to wax paper. Repeat with another batch to finish batter. Let doughnuts cool before icing.
Make The Glaze: Mix the powdered sugar, milk and vanilla in a small pan over low heat. Mix well to combine. Remove the pan from the heat. Pour glaze into a large bowl. Carefully hold a cooled doughnut and "dunk" it in the glaze to coat it; set glazed doughnut on a wire rack to let the glaze harden. Enjoy!
Glazed Chocolate Doughnuts https://www.thegratefulgirlcooks.com/glazed-chocolate-donuts/