Preheat oven to 425 degrees and spray your donut pan with cooking spray.
Mix together sugar, brown sugar and lemon zest in a bowl. Set Aside.
Beat butter in a large mixing bowl until creamy.
Add lemon sugar mixture and vegetable oil and beat until fluffy.
Add egg and beat until combined.
Add vanilla and mix to combine.
Sift flour, baking powder, baking soda and salt together.
Alternate flour and milk, beginning and ending with flour. Mix after each addition until just combined.
Pipe of spoon batter into your prepared donut pan.
Bake for 6-8 minutes or until toothpick comes out clean.
Cool in the pan for about 5 minutes then move to a wire rack to cool completely.
Make the glaze, but mixing powdered sugar, milk, lemon juice and a couple drops of food coloring together.
Once donuts have cooled, Dip the tops of the donuts into the glaze and let dry on a cool rack.