Ingredients (and Why They Matter)
Banana Cake
- ½ cup butter, softened
- 1 ½ cups granulated sugar
- 2 large eggs
- 1 cup full-fat sour cream
- 1 teaspoon vanilla extract
- 2 cups all-purpose flour
- 1 teaspoon baking soda
- ¼ teaspoon salt
- 1 cup mashed ripe bananas (about 3 medium bananas)
Softened butter creams with sugar to build structure and tenderness, trapping air for a light crumb. Granulated sugar sweetens and helps the cake brown evenly. Eggs provide lift and richness, while full-fat sour cream adds moisture, tang, and fat for exceptional softness—better than buttermilk or yogurt in banana cakes.
All-purpose flour gives reliable structure without toughness. Baking soda reacts with bananas’ acidity for lift, and salt balances sweetness. Mashed ripe bananas (the spottier, the better) deliver concentrated flavor, moisture, and natural sweetness that defines banana baked goods.
Cream Cheese Frosting
- ½ cup butter, softened
- 1 package full-fat cream cheese, softened
- 1 teaspoon vanilla extract
- 3 cups powdered sugar
- 2 tablespoons heavy whipping cream
Softened butter and full-fat cream cheese beat into a stable, spreadable base—full-fat cream cheese holds peaks better than low-fat. Vanilla rounds out tanginess. Powdered sugar thickens and sweetens smoothly, while heavy cream adjusts consistency for fluffy spreadability without being runny.
Garnish (Optional)
- Fresh banana slices
- Chopped walnuts
Fresh bananas add color and moisture to the top. Chopped walnuts echo banana bread tradition with crunch and nuttiness.
Step-by-Step Instructions
Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish thoroughly, including corners—nonstick spray or butter plus flour works best for clean release. Line with parchment if desired, leaving overhang for lifting.
In a large bowl, cream the softened butter and granulated sugar with a mixer on medium speed for 2–3 minutes until light, pale, and fluffy; the mixture should ribbon off the paddle. This step builds structure and tenderness. Add eggs one at a time, beating well after each until fully incorporated and smooth. Mix in sour cream and vanilla extract until creamy and uniform.
In a separate bowl, whisk together flour, baking soda, and salt. Add dry ingredients to wet mixture all at once and mix on low speed just until no flour streaks remain—overmixing develops gluten for tough cake. The batter will be thick.
Gently fold in mashed bananas with a spatula until evenly distributed; some streaks are fine. Pour batter into prepared dish and spread evenly with an offset spatula, smoothing top and reaching corners.
Bake 25–35 minutes, rotating halfway, until edges pull slightly from pan sides, top springs back lightly when touched, and toothpick in center comes out clean or with moist crumbs. The surface will be golden with darker edges. Cool completely in pan on wire rack (2+ hours)—warm cake melts frosting.
For frosting, beat softened butter and cream cheese on medium until smooth and lump-free, scraping bowl. Add vanilla. Gradually add powdered sugar 1 cup at a time on low to avoid cloud, then beat on medium-high 2 minutes until fluffy. Add heavy cream and beat until spreadable but thick.
Spread frosting evenly over cooled cake with offset spatula, creating swirls or smooth finish. Garnish with banana slices and walnuts if desired. Slice into squares with sharp knife, wiping between cuts.