2 cups all-purpose flour
1 cup granulated sugar
1 tablespoon baking powder
1/2 teaspoon salt
1 cup milk
1/3 cup vegetable oil
1 large egg
1 teaspoon vanilla extract
1/3 cup unsalted butter, softened
1/2 cup brown sugar
2 tablespoons ground cinnamon
1 cup powdered sugar
2 tablespoons milk
1/2 teaspoon vanilla extract