Ingredients
1 cup (2 sticks) unsalted butter, room temperature, plus more for pan
2 1/2 cups all-purpose flour, plus more for pan
2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon coarse salt
3/4 cup pure maple syrup
1/2 cup granulated sugar
2 large eggs
1 teaspoon vanilla extract
3/4 cup sour cream
1/3 cup pure maple syrup, plus more if needed
3 tablespoons unsalted butter, melted
2 1/2 cups confectioners’ sugar, plus more if needed
Preparation
Make the cake: Preheat oven to 350 degrees. Butter a 9-inch square baking pan; line with parchment, and butter parchment. Dust with flour, tapping out excess. In a medium bowl, whisk together flour, baking powder, baking soda, and salt.
With an electric mixer on medium speed, beat butter, maple syrup, and granulated sugar until pale and fluffy, 3 to 5 minutes. Add eggs, one at a time, beating well after each addition; mix in vanilla.
Reduce mixer speed to low. Add flour mixture in 3 batches, alternating with 2 batches of sour cream; beat until just combined. Transfer batter to prepared pan; smooth top with an offset spatula. Bake until a cake tester comes out clean, about 40 minutes. Transfer pan to a wire rack to cool 10 minutes. Turn out cake onto rack to cool completely.
Make the icing: Combine maple syrup and butter in a bowl. Sift in confectionersâ?? sugar, and whisk until combined. Adjust consistency with more syrup or sugar, if necessary. Spread maple icing over top of cake. Let set, at least 15 minutes, before serving.
