Banana Bread Cake with Cream Cheese Frosting 
Ingredients
For the banana cake:
½ cup (1 stick) unsalted butter, softened to room temperature
1 ½ cups granulated sugar
2 large eggs, at room temperature
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 bananas
For the cream cheese frosting:
½ cup (1 stick) unsalted butter, softened
1 bar (8 ounces) full-fat cream cheese, softened
1 teaspoon vanilla extract
3 cups powdered sugar
2 tablespoons heavy whipping cream
Instructions
Step 1 – Preheat and prepare the pan
Set an oven rack in the middle position. Preheat the oven to 350°F. Spray a 9×13-inch baking pan generously with non-stick cooking spray, making sure to coat the corners and up the sides slightly. Alternatively, grease with butter and dust lightly with flour. Set the pan aside.
Step 2 – Cream the butter and sugar
In a large mixing bowl, combine the softened butter and granulated sugar. Using an electric hand mixer on medium speed (setting 4 or 5), or a stand mixer with a paddle attachment, beat for 2–3 minutes. Stop and scrape down the sides of the bowl with a rubber spatula at least once. The mixture is ready when it looks light, pale, and fluffy, with no visible lumps of butter. Initially it will appear crumbly, but continue beating until it becomes smoother.
Step 3 – Add eggs, sour cream, and vanilla
Add the eggs one at a time, beating for about 15 seconds after each addition. Then add the sour cream and vanilla extract. Beat on medium-low speed for about 1 minute, until the mixture is creamy, uniform in color, and well combined. Scrape down the sides of the bowl again with a rubber spatula to ensure no streaks remain.
Step 4 – Incorporate dry ingredients
In a separate small bowl, whisk together the flour, baking soda, and salt. Whisk for about 20 seconds to evenly distribute the baking soda and salt. Gradually add the dry mixture to the wet mixture, mixing on low speed. Add the flour in three additions, mixing for about 5–10 seconds after each. Stop as soon as the flour disappears and the batter looks uniform. Do not overmix; overmixing will make the cake tough and dense.
Step 5 – Fold in the mashed bananas
Add the mashed bananas to the bowl. Switch to a rubber spatula. Fold gently by cutting the spatula down through the center, scraping the bottom, and bringing the batter up and over the top. Rotate the bowl a quarter turn and repeat. Fold for about 20–30 seconds, just until the bananas are evenly distributed. The batter will be thick, slightly lumpy from the bananas, and pale tan in color.
Step 6 – Bake the cake
Pour the batter into the prepared 9×13-inch pan. Use the spatula to spread it evenly into the corners, smoothing the top. Tap the pan gently on the counter 2–3 times to release any large air bubbles. Place the pan on the middle oven rack. Bake for 25–35 minutes. Do not open the oven door for the first 22 minutes. Start checking at 25 minutes by inserting a wooden toothpick into the center of the cake. If it comes out with a few moist crumbs clinging to it (not wet batter), the cake is done. If the toothpick is wet, bake for another 3–5 minutes and test again. The edges will pull away slightly from the sides of the pan, and the top will be light golden brown with a slight spring when pressed gently with a fingertip.
Step 7 – Cool the cake completely
Remove the pan from the oven and place it on a wire cooling rack. Let the cake cool in the pan for 15 minutes. After 15 minutes, you may run a thin knife around the edges of the pan to loosen the cake, but leave it in the pan. Let the cake cool completely to room temperature. This takes about 1–2 hours. To speed cooling, you can place the pan on a wire rack in a cool spot away from the oven. Do not frost while warm; the frosting will melt and slide off.
Step 8 – Make the cream cheese frosting
About 20 minutes before the cake is fully cooled, prepare the frosting. In a large mixing bowl, combine the softened butter and cream cheese. Both should be at room temperature so they blend smoothly. If they are cold, microwave separately for 10 seconds each. Using a hand mixer on medium speed, beat for 1–2 minutes until the mixture is completely smooth, with no lumps of cream cheese. Scrape down the bowl. Add the vanilla extract, powdered sugar, and heavy whipping cream. Start mixing on low speed to avoid a cloud of powdered sugar, then increase to medium-high speed. Beat for 1–2 minutes until the frosting is thick, fluffy, and spreadable. Stop and scrape the bowl. If the frosting is too thick to spread easily, add 1 more teaspoon of heavy cream and beat for 15 seconds. If too thin or runny, add 2 tablespoons of powdered sugar and beat for 15 seconds.
Step 9 – Frost the cooled cake
Once the cake is completely cool to the touch (no warmth on the top or sides), spread the cream cheese frosting evenly over the top. Use an offset spatula or the back of a large spoon. Start with dollops of frosting around the edges, then push them toward the center. Swirl the top as desired. Do not press hard; the cake is tender and can crumble. Leave a ¼-inch border around the edges to prevent frosting from spilling over the sides.
Step 10 – Garnish and serve
If desired, garnish just before serving. Slice a fresh banana into ¼-inch rounds and arrange them on top of the frosting. Sprinkle with ½ cup of chopped walnuts. To cut clean slices, dip a sharp chef’s knife in hot water and wipe it dry before each cut. Cut into 12 large squares or 18 smaller squares. Serve at room temperature or slightly chilled, as preferred.
Step 11 – Store leftovers
Store any leftover cake in an airtight container in the refrigerator for up to 5 days. Because the frosting contains cream cheese, do not leave the cake at room temperature for more than 2 hours. To serve leftover cake cold, take slices directly from the refrigerator. To bring to room temperature, let slices sit on the counter for 15–20 minutes before serving.
Banana Bread Cake with Cream Cheese Frosting
