1 1/2 cups all-purpose flour
2 teaspoons baking powder
1/2 teaspoon kosher salt
1 cup plain whole-milk yogurt
1 cup plus 1 tablespoon sugar
3 extra-large eggs
1 tablespoon grated grapefruit zest (approximately one large grapefruit)
1/2 teaspoon pure vanilla extract
1/2 cup vegetable oil
1/3 cup freshly squeezed grapefruit juice
For the glaze:
1 cup confectioners’ sugar
2 tablespoons freshly squeezed grapefruit juice