Rich and Tender Banana Cake

Preheat the oven to 350°F with a rack in the center. Lightly grease the sides of an 8" round pan and line the bottom with a parchment round; lightly grease the parchment.  

To make the banana cake: In the bowl of a stand mixer fitted with the flat beater attachment or working in a large bowl with an electric hand mixer, beat the butter and sugar on medium speed until light and fluffy, 3 to 5 minutes. 

Add the egg and vanilla and beat until smooth, then beat in the mashed banana until incorporated; it’s OK if the mixture looks a little separated at this point. Scrape down the sides and bottom of the bowl. 

In a small bowl, whisk together the flour, baking powder, salt, and baking soda.  

Add about half of the dry ingredients to the banana mixture and beat on low speed just to combine. Beat in the sour cream until incorporated, then beat in the remaining dry ingredients until the batter is smooth. Scrape down the sides and bottom of the bowl to incorporate any dry flour. 

Transfer the batter to the prepared pan and spread it evenly with a small offset spatula. 

Bake the cake for 30 to 35 minutes, until a toothpick inserted into the center comes out with a few moist crumbs clinging to it but no raw batter. 

Allow the cake to cool in the pan on a wire rack for 10 to 15 minutes. Turn out the cake onto the rack and flip it right side up; let cool completely before glazing. 

To make the sour cream glaze: Combine all the glaze ingredients in a medium bowl and stir vigorously with a rubber spatula until smooth. The mixture will seem too dry at first but keep stirring and it will gradually come together. Spoon the glaze onto the middle of the cake and, using a small offset spatula, spread it evenly over the top.  

Storage information: Store any leftover banana cake, covered, at room temperature for up to 3 days; freeze for longer storage.