Banana Sheet Cake

A slice of Banana Bread Cake on a small plate set on a white marble countertop.

Banana Sheet Cake is like banana bread in cake form, soft, moist and full of sweet banana flavor. Sour cream keeps it tender, while walnuts add a satisfying crunch. The brown butter frosting gives it a rich, nutty sweetness that makes every bite irresistible. It's the perfect way to turn ripe bananas into an easy, crowd-pleasing dessert that feels bakery special.

Course Dessert

Cuisine American

Keyword Banana Cake Walnut Recipe, Banana Sheet Cake

Prep Time 20

Cook Time 30

Servings servings

Calories 591kcal

Author Heather

Ingredients

Cake

1 1/2 cups granulated sugar
1 cup sour cream
1/2 cup neutral oil *sunflower or avocado
2 large eggs *room temperature
1 1/2 cups mashed ripe bananas *about 3 large, see Note #1 below
2 teaspoons vanilla extract
2 cups all-purpose flour
1 teaspoon salt *see note #2 below
1 1/2 teaspoons baking soda
1 teaspoon ground cinnamon
1/2 cup chopped walnuts *see Note #3 below

Browned Butter Frosting

1/2 cup unsalted butter
4 cups powdered sugar *aka confectioners' sugar
2 teaspoons vanilla extract
6 tablespoons milk *plus more if needed for consistency

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Instructions

Cake

Preheat oven to 375℉. Grease and lightly flour a 9x13-inch baking pan or line with parchment paper for easy removal.
In a large mixing bowl, beat together the sugar, sour cream, oil and eggs until smooth and slightly pale, about 2 minutes.
Mix in the mashed bananas and vanilla on low speed until just combined.
In a separate bowl, whisk together the flour, salt, baking soda and cinnamon.
Gradually add the dry ingredients to the wet mixture, mixing just until combined. (Do not over mix. A few small streaks of flour are fine.)
Gently fold in chopped walnuts until evenly distributed.
Pour the batter into the prepared pan and smooth the top. Bake 28-35 minutes, or until a toothpick inserted in the center comes out clean.
Cool completely in the pan on a wire rack before frosting.

Browned Butter Frosting

In a small saucepan, melt butter over medium heat. Continue cooking, stirring the butter often, until the butter turns golden brown and smells nutty, about 4-5 minutes. Immediately pour into a mixing bowl to stop the cooking.
Add powdered sugar, vanilla and 3 tablespoons of the milk. Beat on low, gradually increasing to medium speed. Add the remaining milk, 1 tablespoon at a time, until the frosting is smooth and spreadable.
Spread the frosting evenly over the cooled cake. Garnish with additional chopped walnuts. Let set for 15 minutes before slicing.

Video

Notes

Note #1- Use very ripe bananas. The darker the peel, the better the flavor and sweetness.

Note #2- If using Maldon's Sea Salt, grind the large flakes with a mortar and pestle before adding to the batter.

Note #3- For added depth of flavor, toast the walnuts before folding them in. Spread the walnuts on a baking sheet and bake at 350℉ for 7 to 9. minutes, stirring once or twice, until they smell fragrant and turn lightly golden.

Note #4- For the best results, use room temperature eggs and sour cream. This helps the ingredients blend smoothly, giving you a soft and tender cake.

Nutrition