Mix the flour, sugar, baking powder, and salt in a large bowl. Stir milk, oil, egg, and vanilla extract into the flour mixture until the batter is just blended.
1 ½ cups all-purpose flour, ½ cup granulated sugar, 2 teaspoon baking powder, ½ teaspoon salt, ¾ cup milk, ¼ cup vegetable oil, 1 large egg, ½ teaspoon vanilla extract