• Preheat your oven to 350°F (176°C) and line a cupcake pan with cupcake liners.
• In a medium bowl, combine the flour, baking powder, and salt. Whisk together thoroughly.
• In a large mixer bowl, beat together the unsalted butter, sugar, vegetable oil, and vanilla extract until light and fluffy, about 3 to 5 minutes.
• Add the eggs one at a time, mixing until mostly combined after each addition.
• Add half of the dry mixture and mix briefly, then pour in the milk and mix until well combined.
• Add the remaining dry ingredients and mix until smooth, being careful not to over-mix.

Baking

• Fill each cupcake liner about ¾ full with batter. Bake for 15-18 minutes or until a toothpick inserted comes out clean.
• Remove cupcakes from the oven and let them cool on a wire rack.

Making the Frosting

• Beat the unsalted butter in a mixing bowl until smooth. Gradually add the powdered sugar, mixing until smooth and creamy.
• Stir in the vanilla extract, salt, and enough water or milk to achieve desired consistency.

Finishing Touch

• Pipe the frosting onto the cooled cupcakes.