Quick Recipe Version (TL;DR)
Quick Ingredients
- 8 tbsp (113 g) unsalted butter
- 3 large very ripe bananas, mashed (about 1 1/2 cups / 340 g)
- 3/4 cup (150 g) light brown sugar, packed
- 1/4 cup (50 g) granulated sugar
- 2 large eggs, room temp
- 2 tsp vanilla extract
- 1/2 cup (120 g) full-fat Greek yogurt or sour cream
- 1 3/4 cups (220 g) all-purpose flour
- 1 tsp baking soda; 1/2 tsp baking powder
- 3/4 tsp fine sea salt; 1/2 tsp ground cinnamon
- 3/4 cup (85 g) walnuts, chopped and toasted
- 4 oz (115 g) dark chocolate (60–70%), finely chopped
- Optional: 1–2 tsp turbinado sugar for topping
Do This
- 1) Heat oven to 350°F (177°C). Grease and parchment-line a 9×5-in loaf pan. Toast walnuts 8 minutes; cool.
- 2) Brown butter in a light pan over medium heat until nutty and amber, 5–8 min. Reserve 1 tbsp for swirl; cool remaining 5 min.
- 3) Whisk cooled brown butter with sugars. Whisk in eggs, mashed bananas, vanilla, and yogurt.
- 4) Whisk flour, baking soda, baking powder, salt, and cinnamon. Fold into wet just to combine. Fold in most walnuts.
- 5) Remove 1/2 cup batter to a bowl. Melt chocolate with reserved 1 tbsp brown butter; whisk into that 1/2 cup to make chocolate batter.
- 6) Spread about 2/3 plain batter in pan. Dollop half chocolate batter; swirl. Add remaining plain batter and remaining chocolate; swirl lightly. Top with reserved walnuts and turbinado sugar.
- 7) Bake 55–65 min until a skewer has a few moist crumbs and center is 200–205°F (93–96°C). Cool 10 min, then fully on a rack before slicing.
Why You’ll Love This Recipe
- Browned butter adds deep, nutty aroma without extra steps on the mixer.
- Ribbons of dark chocolate create gooey pockets in every slice.
- Toasted walnuts provide irresistible crunch against a plush, tender crumb.
- Simple, reliable method with clear cues and make-ahead friendly.
Grocery List
- Produce: 3 large very ripe bananas
- Dairy: Unsalted butter, 2 large eggs, full-fat Greek yogurt or sour cream
- Pantry: All-purpose flour, light brown sugar, granulated sugar, baking soda, baking powder, fine sea salt, ground cinnamon, pure vanilla extract, dark chocolate (60–70%), walnuts, turbinado sugar, parchment paper
Full Ingredients
Banana Bread Batter
- 8 tbsp (113 g) unsalted butter
- 3 large very ripe bananas, mashed (about 1 1/2 cups / 340 g)
- 3/4 cup (150 g) light brown sugar, packed
- 1/4 cup (50 g) granulated sugar
- 2 large eggs, at room temperature
- 2 tsp vanilla extract
- 1/2 cup (120 g) full-fat Greek yogurt or sour cream, room temperature
- 1 3/4 cups (220 g) all-purpose flour
- 1 tsp baking soda
- 1/2 tsp baking powder
- 3/4 tsp fine sea salt
- 1/2 tsp ground cinnamon
- 3/4 cup (85 g) walnuts, chopped and toasted (reserve 2 tbsp for topping)
Chocolate Swirl
- 4 oz (115 g) dark chocolate (60–70%), finely chopped
- 1 tbsp reserved brown butter (from above)
Topping (Optional)
- 2 tbsp chopped toasted walnuts (from above)
- 1–2 tsp turbinado sugar
Step-by-Step Instructions
Step 1: Prep the pan and toast the nuts
Preheat the oven to 350°F (177°C). Grease a 9-by-5-inch loaf pan and line it with a parchment sling that overhangs the long sides for easy removal. Spread the chopped walnuts on a small baking sheet and toast in the oven for 8 minutes, shaking once, until fragrant and a shade darker. Set aside to cool.
Step 2: Brown the butter
Place the 8 tablespoons (113 g) butter in a light-colored saucepan over medium heat. Cook, stirring and scraping the bottom often, as it melts, then foams, then turns golden with brown flecks, 5–8 minutes total. When it smells nutty and the milk solids are toasty brown, immediately pour into a heatproof bowl to stop the cooking. Measure out and reserve 1 tablespoon of the brown butter for the chocolate swirl. Let the remaining brown butter cool for 5–7 minutes until just warm, not hot.
Step 3: Mix the wet ingredients
In a large bowl, whisk the warm brown butter with the brown sugar and granulated sugar until glossy and slightly thick, 30–45 seconds. Whisk in the eggs one at a time until smooth and emulsified. Add the mashed bananas, vanilla, and yogurt (or sour cream) and whisk until well combined.
Step 4: Whisk the dry ingredients
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon. This distributes the leaveners evenly so the loaf rises uniformly.
Step 5: Combine and fold in walnuts
Switch to a flexible spatula. Add the dry mixture to the wet mixture and fold gently just until no dry streaks remain; a few small lumps are fine. Fold in about 2/3 of the toasted walnuts, reserving a couple of tablespoons for the top. Scoop out 1/2 cup of the batter into a small bowl and set aside for the swirl.
Step 6: Make the chocolate swirl and assemble
In a microwave-safe bowl (or over a double boiler), melt the chopped dark chocolate with the reserved 1 tablespoon brown butter in 15–20 second bursts, stirring between bursts until smooth and glossy. Cool 1 minute, then whisk the melted chocolate into the reserved 1/2 cup batter to make a chocolate batter.
Spread about 2/3 of the plain batter into the prepared pan. Dollop half of the chocolate batter over it in big spoonfuls, then use a butter knife to gently swirl in a few figure-8 motions. Add the remaining plain batter on top, then the remaining chocolate batter, and swirl lightly again (two or three passes—do not over-swirl). Tap the pan once on the counter to settle. Sprinkle with the reserved walnuts and turbinado sugar.
Step 7: Bake, cool, and slice
Bake until the loaf is deeply golden, the center springs back, and a skewer inserted near the center comes out with a few moist crumbs (no wet batter), 55–65 minutes. An instant-read thermometer should read 200–205°F (93–96°C) in the center. If the top is browning too quickly, tent loosely with foil after 45 minutes. Cool in the pan for 10 minutes, then lift out using the parchment and cool completely on a rack for at least 1 hour before slicing.
Pro Tips
- Use very ripe, heavily speckled bananas; weigh to 340 g mashed for consistent moisture.
- To quickly ripen bananas, bake unpeeled at 300°F (150°C) for 15–20 minutes until blackened; cool, peel, and drain excess liquid.
- Weigh your flour (220 g). If using cups, fluff, spoon, and level to avoid a dense loaf.
- For distinct marbling that doesn’t sink, always mix some batter into the melted chocolate before swirling.
- Check doneness with a thermometer (200–205°F); overbaking dries banana bread.
Variations
- Pecan or hazelnut swap: Replace walnuts 1:1 with toasted pecans or hazelnuts.
- Extra chocolate pockets: Fold 1/2 cup (85 g) dark chocolate chunks into the plain batter in addition to the swirl.
- Banana bread muffins: Divide between 12 lined muffin cups, swirl chocolate into each; bake at 350°F (177°C) for 20–24 minutes.
Storage & Make-Ahead
Wrap the cooled loaf tightly and store at room temperature for up to 3 days or refrigerate for up to 5 days. For longer storage, slice and freeze pieces in a single layer, then transfer to a freezer bag for up to 3 months. Thaw at room temperature or rewarm slices in a 300°F (150°C) oven for 8–10 minutes or in a toaster oven until the chocolate is just melty again.
Nutrition (per serving)
Approximate for 1 of 10 slices: 410 calories; 23 g fat; 47 g carbohydrates; 6 g protein; 3 g fiber; 24 g sugars; 270 mg sodium. Values will vary with ingredient brands and optional toppings.
