cinnamon swirl loaf cake

Instructions

1. Preheat oven to 350°F and line a 9 x 5-inch loaf pan with parchment paper, letting excess extend over sides of pan. Spray parchment paper lightly with nonstick spray.
2. Beat butter and sugar in a large mixer bowl at medium speed until light and fluffy; beat in egg and vanilla. Combine yogurt and buttermilk in a small bowl. Reduce speed to low and add half of flour mixture, beating just to combine. Add yogurt mixture, then finish with remaining flour mixture.
3. Combine sugar and cinnamon in a small bowl. Spoon half the batter into prepared pan and smooth top with an offset spatula. Tap pan sharply to reduce air bubbles. Sprinkle 2 1/2 tablespoons of cinnamon sugar over the batter. Spoon the remaining batter evenly over the cinnamon sugar and smooth with an offset spatula; tap pan sharply again. Sprinkle remaining cinnamon sugar over the top of the batter.
4. Bake for 42 to 45 minutes, until cake springs back to the touch and a toothpick inserted in the center comes out clean or with a few crumbs attached. Cool in pan on a wire rack for 10 minutes; carefully lift cake from pan and cool completely.
5. For the glaze, whisk together melted butter, salt, vanilla, powdered sugar, and milk in a small bowl. Drizzle glaze over cake and and let set before serving.