Preheat the oven to 425˚F (218˚C). Lightly grease a mini donut pan.

In a small bowl, mix the sugar and lemon zests together. Add brown sugar and set aside.

In a large mixing bowl, beat the butter for 2 minutes. Add lemon sugars and vegetable oil, and beat until fluffy, about 3 minutes.

Add the egg and beat to combine. Stir in the baking powder, baking soda, salt, and vanilla with a spatula.

Stir and add the flour and milk to the butter mixture alternately in 3 additions, starting and finishing with the flour. Mix until just combined.

Spoon the batter into a piping bag or Ziploc bag, and fill the donut pan with batter up to the rim.

Bake for about 6 – 8 minutes, testing with a toothpick for doneness. The toothpick should come out clean.

Remove from oven and cool in the pan for 5 minutes. Transfer to a cooling rack to cool completely.

For the glaze, in a medium bowl, add powdered sugar. Add the milk, 1½ tablespoons lemon juice, and pink food coloring (if using). Whisk until smooth, adding more lemon juice if the frosting is too thick.

Glaze the donuts and let them set for 20 minutes.