Preheat the oven to 350°F. Line a muffin pan with paper liners and set aside.
In a large bowl, whisk together the eggs and sugar until the sugar has completely dissolved.
Whisk in the orange zest, vanilla extract, and milk.
Sift in the flour, baking powder, and salt. Whisk together to mostly combine.
Add the vegetable oil and whisk together until the batter is completely smooth.
Divide the batter evenly into the prepared muffin cups. Lightly tap the cupcake pan on the counter 2-3 times to help even out the batter and get rid of any large air bubbles.
Bake for 25-30 minutes, until the tops are golden brown and an inserted toothpick comes out clean.
Allow them to cool for 10 minutes before serving.
Notes
This is a quick and easy recipe to make by hand using just a mixing bowl and whisk, but feel free to use a hand mixer or stand mixer with a whisk attachment.
Mantecadas have a signature look with their red cupcake liners, but feel free to use any color.