One-Bowl Banana Nut Cake

This banana nut cake is the one to make when you’ve got a couple of spotty bananas on the counter and you want a real-deal cake, not a quick bread pretending to be something it’s not.

It’s tender and buttery, studded with toasted walnuts, and the whole thing comes together in one bowl with minimal fuss. Perfect for a lazy Sunday or a Tuesday night treat.

What Makes This Banana Nut Cake So Good

The crumb is soft and cakey, with a tight but light texture that holds up to a thick swipe of cream cheese frosting or a simple dusting of powdered sugar.

Using melted butter skips the creaming step, and sour cream guarantees it stays moist for days. You’ll taste the banana clearly, not just a whisper of it.

Ingredients

• 2 overripe medium bananas, mashed (about 1 cup): the blacker the peel, the sweeter the cake.
• 1/2 cup unsalted butter, melted: let it cool slightly before mixing.
• 3/4 cup packed light brown sugar: dark brown sugar works for a deeper molasses note.
• 1 large egg, at room temperature: cold eggs can make the batter seize.
• 1 teaspoon vanilla extract: pure vanilla gives the best background warmth.
• 1/2 cup full-fat sour cream: use full fat for the most tender crumb.
• 1 1/2 cups all-purpose flour: spooned and leveled, not scooped.
• 1 teaspoon baking soda: the bananas and sour cream activate it.
• 1/2 teaspoon fine sea salt: don’t skip it, it balances the sweetness.
• 1/2 teaspoon ground cinnamon: a subtle spice that lets the banana shine.
• 3/4 cup chopped walnuts, toasted: pecans work just as well if you prefer.

Variations / Substitutions

• No sour cream? – plain Greek yogurt is a solid swap; it will be slightly less rich but still moist.
• Dairy-free option – use melted coconut oil and a thick non-dairy yogurt; the texture will be a bit denser.
• Switch up the nuts – toasted pecans, almonds, or even macadamia nuts all work, just keep the quantity the same.
• Add chocolate – fold in 1/2 cup dark chocolate chips along with the nuts for a banana-chocolate moment.
• For a chocolate twist, try my Double Chocolate Banana Bread.

How to Make Banana Nut Cake

Step 1: Mix the Wet Ingredients

Preheat your oven to 350°F (175°C) and grease a 9×5-inch loaf pan. In a large bowl, whisk together the 1/2 cup melted butter, 3/4 cup brown sugar, 1 cup mashed banana, 1 large egg, 1 teaspoon vanilla, and 1/2 cup sour cream until smooth and well blended.

The mixture will look a little lumpy from the banana, and that’s exactly right. You don’t need to whip any air into it—just a good whisk to bring everything together.

Step 2: Add the Dry Ingredients

Sprinkle the 1 1/2 cups flour, 1 teaspoon baking soda, 1/2 teaspoon salt, and 1/2 teaspoon cinnamon over the wet mixture. Switch to a rubber spatula and gently stir just until no dry streaks remain.

Stop as soon as the flour disappears. A few small lumps in the batter are fine; overmixing will make the cake tough.

Step 3: Fold in the Walnuts

Add the 3/4 cup toasted chopped walnuts and fold them in with the spatula, using a few broad strokes. The batter will be thick and speckled with nuts.

Toasting the walnuts beforehand deepens their flavor and keeps them crunchy after baking. If you’re short on time, raw walnuts still work, but the toasted ones are worth the few extra minutes.

Step 4: Bake the Cake

Scrape the batter into the prepared loaf pan and smooth the top. Bake at 350°F (175°C) for 50 to 60 minutes, until a toothpick inserted in the center comes out with a few moist crumbs clinging to it.

If the top is browning too quickly before the center is done, tent a piece of foil loosely over the pan after 40 minutes. The house will smell glorious.

Step 5: Slice and Serve

Let the cake cool in the pan for 10 minutes, then run a knife around the edge and turn it out onto a wire rack to cool completely. Slice with a serrated knife while it’s still barely warm, or let it cool fully for cleaner cuts.

Dust with powdered sugar if you like, or spread a thick layer of cream cheese frosting on top. Cake keeps well at room temperature for a day or two.

A Few Notes Before You Start

• Measure your flour correctly by spooning it into the cup and leveling off. Scooping directly from the bag packs in too much flour and makes a dense cake.
• If your bananas aren’t ripe yet, bake them in their skins at 300°F (150°C) for 15 minutes until black, then cool and peel.
• Swap half the walnuts for dark chocolate chips if you’re feeding a crowd that loves a little melty chocolate in every bite.
• Don’t open the oven door during the first 45 minutes of baking, or the cake may sink in the center.

Bake times by pan size:

Storing Leftover Cake

• Refrigerate: wrap the cake tightly in plastic wrap and keep in the fridge for up to 4 days. Bring slices to room temperature before serving for the best texture.
• Freeze: wrap the cooled loaf first in plastic, then in foil, and freeze up to 3 months. Thaw overnight in the fridge.

Frequently Asked Questions

Can I use whole wheat flour?

I wouldn’t. Whole wheat flour makes the crumb heavy and dry, so stick with all-purpose or a 1:1 gluten-free blend.

Why did my cake sink in the middle?

It’s usually one of two things: opening the oven door too early, or the loaf was underbaked. A toothpick with wet batter means it needs more time.

Can I skip the nuts?

Sure. Leave them out entirely and the cake will still be tender. You can replace them with an extra 1/4 cup of mashed banana for extra moisture.

Can I use oil instead of butter?

You can, but the flavor won’t be as rich. Use an equal amount of a neutral oil, like vegetable or canola.

Can I make this gluten-free?

Yes. Swap the all-purpose flour for a 1:1 gluten-free baking blend that contains xanthan gum. The texture will be a shade more delicate but still very good.

Banana Nut Cake Recipe

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 55 minutes mins

Total Time 1 hour hr 10 minutes mins

Servings: 10 servings

Calories: 280

Ingredients Method Notes

Ingredients

  

• 2 overripe medium bananas, mashed (about 1 cup)
• 1/2 cup unsalted butter, melted
• 3/4 cup packed light brown sugar
• 1 large egg, at room temperature
• 1 teaspoon vanilla extract
• 1/2 cup full-fat sour cream
• 1 1/2 cups all-purpose flour
• 1 teaspoon baking soda
• 1/2 teaspoon fine sea salt
• 1/2 teaspoon ground cinnamon
• 3/4 cup chopped walnuts, toasted

Method

 

1. Preheat oven to 350°F (175°C). Grease a 9×5-inch loaf pan.
2. In a large bowl, whisk melted butter, brown sugar, mashed banana, egg, vanilla, and sour cream until smooth.
3. Sprinkle flour, baking soda, salt, and cinnamon over the wet mixture. Stir with a spatula just until no dry streaks remain.
4. Fold in toasted walnuts with a few broad strokes.
5. Pour batter into the pan, smooth the top, and bake 50 to 60 minutes until a toothpick comes out with moist crumbs.
6. Cool in the pan 10 minutes, then turn out onto a wire rack. Slice and serve warm or at room temperature.

Notes

Cool the cake completely before slicing if you want neat, even slices. Store at room temperature for up to 2 days, or in the fridge wrapped tightly for longer freshness. For the best banana flavor, use bananas so ripe the peels are mostly black.