Quick Recipe Version (TL;DR)
Quick Ingredients
- 1/2 cup (113 g) unsalted butter, browned and cooled
- 3 large very ripe bananas, mashed (1 1/2 cups / 340 g)
- 3/4 cup (150 g) packed dark brown sugar + 1/4 cup (50 g) granulated sugar
- 2 large eggs
- 1/3 cup (80 g) sour cream
- 2 tsp vanilla extract
- 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 tsp ground cinnamon
- 1 cup (110 g) walnuts, toasted and chopped
- 1 tbsp demerara or turbinado sugar (optional, for top)
Do This
- 1. Heat oven to 325°F (165°C). Line a 9×5-inch loaf pan with parchment; lightly grease.
- 2. Toast walnuts on a sheet pan, 8–10 minutes; cool, then chop.
- 3. Brown butter in a light saucepan 4–6 minutes until nutty and amber; cool 5 minutes.
- 4. Mash bananas; whisk in sugars, eggs, sour cream, vanilla, and cooled brown butter.
- 5. Whisk flour, baking soda, baking powder, salt, cinnamon. Fold into wet; stir in walnuts.
- 6. Fill pan, sprinkle demerara. Bake 60–70 minutes until 200–205°F inside. Cool 20 minutes, slice warm with salted butter.
Why You’ll Love This Recipe
- Super-moist crumb thanks to brown butter, ripe bananas, and a touch of sour cream.
- Toasted walnuts add deep, nutty crunch in every bite.
- Warm cinnamon and vanilla perfume the loaf without overpowering the banana flavor.
- Fabulous fresh from the oven with a swipe of salted butter.
Grocery List
- Produce: 3 very ripe bananas
- Dairy: Unsalted butter, sour cream, eggs, salted butter (for serving)
- Pantry: All-purpose flour, dark brown sugar, granulated sugar, walnuts, vanilla extract, baking soda, baking powder, ground cinnamon, fine sea salt, demerara sugar (optional), parchment or nonstick spray
Full Ingredients
Banana–Nut Bread
- 1/2 cup (113 g) unsalted butter
- 3 large very ripe bananas, mashed (1 1/2 cups / 340 g)
- 3/4 cup (150 g) packed dark brown sugar
- 1/4 cup (50 g) granulated sugar
- 2 large eggs, at room temperature
- 1/3 cup (80 g) full-fat sour cream
- 2 tsp pure vanilla extract
- 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 tsp ground cinnamon
- 1 cup (110 g) walnut halves, toasted and chopped
For the Pan and Topping
- Softened butter or nonstick spray, for the pan
- 1 tbsp demerara or turbinado sugar (optional, for a crunchy top)
To Serve
- Salted butter, room temperature

Step-by-Step Instructions
Step 1: Heat the oven and prepare the pan
Preheat the oven to 325°F (165°C) with a rack in the center. Grease a 9×5-inch loaf pan and line it with a parchment sling, leaving overhang on the long sides for easy lifting. Lightly grease the parchment as well.
Step 2: Toast the walnuts
Spread walnuts on a baking sheet and toast in the preheated oven for 8–10 minutes, until fragrant and a shade darker. Cool completely, then chop into pea-size pieces. Toasting keeps the nuts crunchy in the moist loaf.
Step 3: Brown the butter
Add the butter to a light-colored saucepan over medium heat. Melt, then cook, swirling often, 4–6 minutes until the butter foams, the milk solids turn deep golden brown, and it smells nutty. Immediately scrape into a heatproof bowl to stop the cooking and cool 5–10 minutes until warm, not hot.
Step 4: Mix the wet ingredients
In a large bowl, mash the bananas until mostly smooth (a few small lumps are fine). Whisk in the brown sugar and granulated sugar until glossy. Whisk in the eggs one at a time, then the sour cream and vanilla. Slowly drizzle in the cooled brown butter while whisking to emulsify.
Step 5: Combine dry ingredients and bring the batter together
In a separate bowl, whisk the flour, baking soda, baking powder, salt, and cinnamon. Add the dry ingredients to the banana mixture and fold gently with a spatula just until a few streaks of flour remain. Fold in the toasted walnuts. Do not overmix; the batter should be thick and slightly lumpy.
Step 6: Bake
Scrape the batter into the prepared pan and smooth the top. Sprinkle with demerara sugar if using. Bake 60–70 minutes, rotating the pan once at 45 minutes, until a toothpick inserted in the center comes out mostly clean (a few moist crumbs are okay) and the internal temperature reads 200–205°F (93–96°C). If the top is browning too quickly, tent loosely with foil for the last 10–15 minutes.
Step 7: Cool, slice, and serve
Cool in the pan for 10–15 minutes to set the crumb, then lift out using the parchment and cool another 20 minutes on a rack. Slice while still pleasantly warm and serve with salted butter. The flavor deepens after several hours, but it is irresistible warm.
Pro Tips
- Use very ripe bananas with lots of brown spots; they mash smoother and taste sweeter. If yours are pale, roast whole bananas on a sheet at 300°F (150°C) for 15–20 minutes, cool, and proceed.
- Weigh ingredients for best consistency. Flour compacts easily; 1 3/4 cups equals 220 g.
- Brown butter should be warm, not hot, before adding to the batter to avoid scrambling eggs.
- For a neat slice, cool at least 30 minutes. For a gooey, bakery-style slice, go warm and use a serrated knife.
- Check doneness with internal temperature: 200–205°F in the center gives a moist but set crumb.
Variations
- Chocolate-Chip Banana Walnut: Fold in 3/4 cup (130 g) semisweet chocolate chips with the walnuts.
- Maple Pecan: Swap walnuts for pecans and replace 1/4 cup (50 g) sugar with 1/4 cup (60 ml) pure maple syrup; bake 5–10 minutes longer if needed.
- Gluten-Free: Use a 1:1 gluten-free baking flour by weight (220 g). Let the batter rest 10 minutes before baking.
Storage & Make-Ahead
Cool completely, then wrap tightly. Store at room temperature up to 3 days. For longer storage, slice and freeze with parchment between slices in a zip-top bag for up to 3 months; thaw at room temp or toast from frozen. Make-ahead components: toast nuts up to 3 days in advance; brown butter and refrigerate up to 5 days (re-melt gently and cool before using). Mix dry ingredients and keep sealed at room temperature up to 1 week.
Nutrition (per serving)
Approximate per slice (1/10 loaf, without serving butter): 380 calories; 20 g fat (7 g saturated); 44 g carbohydrates; 2 g fiber; 23 g total sugars; 6 g protein; 325 mg sodium.


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