Buttermilk Banana Cake

Preheat oven to 350°. Butter a 9"-diameter cake pan; line the bottom with a parchment paper round. Butter parchment. Whisk 2 cups (250 g) all-purpose flour, ½ tsp. baking powder, ½ tsp. baking soda, ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt, and ½ tsp. ground cardamom in a medium bowl.

Beat ½ cup (1 stick) unsalted butter, room temperature, ¾ cup (150 g) granulated sugar, and ¾ cup (packed; 150 g) light brown sugar in the bowl of a stand mixer fitted with the paddle attachment on high speed until combined and pale, about 3 minutes. Reduce speed to medium and mix in 2 large eggs, room temperature and 1 tsp. vanilla extract, then 2 ripe bananas, peeled, flesh finely mashed, scraping down sides of bowl as needed.

Reduce speed to medium-low and mix in half of dry ingredients, then beat in 1 cup buttermilk, room temperature. Using a rubber spatula, mix in remaining dry ingredients, making sure to scrape bottom of bowl so everything gets incorporated.

Scrape batter into prepared pan and smooth surface. Bake cake until golden brown, slightly puffed, and a tester inserted into the center comes out clean, 50–55 minutes. Transfer to a wire rack and let cool.

Meanwhile, whisk 1½ cups (165 g) powdered sugar, a pinch of kosher salt, remaining ¼ cup buttermilk, room temperature, and remaining ½ tsp. vanilla extract in a small bowl to combine.

Turn out cooled cake onto rack or a plate and turn right side up. Pour glaze over top of cake, then sprinkle with flaky sea salt and a pinch of cardamom.