Pink Grapefruit Cupcakes

Name: Pink Grapefruit Cupcakes
Prep time: 15 min
Cook time: 12 min
Total time: 27 min
Cuisine: American
Ingredients: ½ cup unsalted butter (, at room temperature (113 grams)); ½ cup granulated sugar ((115 grams)); 1 large egg; ¼ cup whole milk ((2 fl oz)); 1 teaspoon vanilla extract; 1 cup all-purpose flour ((124 grams)); 1 ½ teaspoons baking powder ((4 grams)); ½ teaspoon salt ((2 grams)); 1 tablespoon grapefruit zest; ½ cup powdered sugar (, sifted (50 grams)); 2 tablespoons fresh grapefruit juice