The Beautiful Banana Muffins You'll Want for School Mornings, Coffee Breaks, and Everything in Between

1. Adjust oven rack to middle position and heat oven to 400℉ (175℃). Line a 12-cup muffin tin with paper liners.
   

2. In a medium bowl, whisk flour, oats, salt, baking soda, and baking powder until combined; set aside.
   

3. In a large bowl, use a potato masher or large fork to mash 2 whole bananas and sour cream together until fairly smooth; set aside. Halve remaining 4 bananas crosswise, then halve lengthwise (you should have 16 banana pieces total); set aside.
   

4. In a large nonstick or cast-iron skillet set over medium-high heat, melt 2 tablespoons (28 g) butter. Add banana slices, flat-side down, and cook until golden brown and softened, flipping as needed, 5 to 7 minutes. Transfer to a separate bowl.
   

5. In the now-empty skillet, add remaining 6 tablespoons (85 g) butter, and cook over medium-high heat, stirring constantly with a rubber spatula, until butter is light golden brown and has a nutty aroma, 2 to 4 minutes. Return browned bananas to skillet, and continue to cook, stirring and flipping banana mixture frequently, until bananas are mostly broken down and the mixture turns dark golden brown and has a deep caramelized nutty banana aroma, 6 to 8 minutes. Off heat, stir in brown sugar, whisking constantly, until sugar is fully dissolved, about 1 minute. Transfer banana mixture back to the now-empty bowl. Let sit until slightly cooled, about 10 minutes.

6. For the Streusel: While bananas cool, make streusel topping: In a medium bowl, stir together flour, brown sugar, oats, melted butter, and salt until mixture resembles wet sand; set aside.
   

7. Stir cooled banana mixture into mashed banana-sour cream mixture. Using a potato masher or large fork, again mash the banana mixture until mostly smooth. Whisk in eggs and vanilla until combined. Using a spatula, stir in flour mixture until just combined. Fold in walnuts or pecans, if using. Evenly divide batter between prepared muffin cups (about 1/4 cup per muffin). Divide streusel evenly over muffins (about 1 tablespoon per muffin).
   

8. Bake for 5 minutes, then reduce heat to 350°F (175°C) and continue baking until muffins are domed, golden brown, and a toothpick or cake tester inserted into the center comes out with a few moist crumbs, 15 to 18 minutes.
   

9. Transfer to a wire rack and let stand in tin for 5 minutes. Carefully remove muffins from tin and allow to cool completely on wire rack, about 20 minutes. Serve or transfer to a storage container.

Special Equipment

Large nonstick or cast-iron skillet, 12-cup muffin pan, muffin liners, toothpick or cake tester, wire rack

Make-Ahead and Storage

The streusel can be made up to 1 day in advance and refrigerated in an airtight container until ready to use.

Once completely cooled, muffins can be stored at room temperature in an airtight container for up to 3 days. 

To freeze muffins, arrange them in a single layer on a 9- by 13-inch rimmed baking sheet. Once frozen, transfer to a zip-top bag. Alternatively, muffins can be wrapped individually in plastic wrap, followed by aluminum foil. Muffins can be frozen for up to 2 months. Let muffins thaw in the fridge overnight before serving. 

Muffins can be served cold, at room temperature, or gently reheated in a microwave or 325°F (160°C) oven before serving.