Heat oven to 350℉/177℃.
Line a cupcake tin with paper liners, or spray with baking spray. Set aside.
In a medium bowl, whisk together flour, sugar, baking powder, and salt. Set aside.
In a small bowl, whisk together eggs, egg yolk, milk, oil, and vanilla.
Pour wet ingredients over dry ingredients.
Whisk until smooth.
Use a 3 Tablespoon scoop to portion dough, or fill cavities ¾ full.
Bake for 20 minutes, or until cupcakes test done.