Heat oven to 350℉/177℃.
Line muffin cups with cupcake liners, or spray with baking spray. Set aside.
In a medium bowl, beat egg whites, ¼ cup sugar, and cream of tartar to medium peaks. Set aside.
Whisk together flour, 1 cup sugar, baking powder, and salt. Set aside.
In a large bowl, combine egg yolks, vegetable oil, milk, and vanilla.
Whisk until blended.
Slowly mix dry ingredients into wet ingredients.
Continue whisking until smooth.
Fold in meringue in 2 parts.
Divide batter into prepared pans, filling each cup ¾ full.
Bake for 15-20 minutes until cupcakes test done.