Three overripe bananas in a one-bowl batter with a brown sugar cinnamon streusel baked on top. No sour cream or yogurt, just pantry staples, and the streusel goes crisp as it cools. About an hour in the oven.
Make the streusel first. Combine the flour, brown sugar, and cinnamon in a small bowl. Cut in the cold butter with a fork or your fingertips until you have crumbs ranging from breadcrumb to pea-sized. Set aside.
3 tablespoon All purpose flour, ¼ cup brown sugar, ½ teaspoon Cinnamon powder, 2 tablespoon Salted butter
For the bread
Heat the oven to 350°F. Grease a 9x5 loaf pan and line it with parchment, leaving an overhang on the long sides.
Mash the bananas with a fork until mostly smooth, leaving a few small lumps.
3 large bananas
Whisk the wet ingredients. Melted butter, sugar, and eggs until combined, then fold in the mashed bananas.
⅓ cup unsalted butter, ⅔ cup White sugar, 2 large Eggs, 3 large bananas
Add the dry ingredients. Flour, baking soda, baking powder, salt, cinnamon, and nutmeg. Stir until the flour streaks just disappear. Do not overmix.
Sprinkle the streusel evenly over the batter, right up to the edges. Don't press it down.
Bake 50 to 60 minutes, checking at 50. A skewer should come out with a few moist crumbs. Tent loosely with foil if the streusel browns before the loaf is done.
Cool 15 minutes in the pan, then lift out onto a rack and cool completely before slicing.
Notes
Makes one 9x5 loaf, about 10 to 12 slices.Bananas should be heavily spotted to mostly black. If there's still yellow showing, they aren't sweet enough and won't mash smoothly. In a hurry, bake them unpeeled at 300°F for 15 to 20 minutes until the skins blacken, then cool before peeling.Measure the flour by spooning and leveling. Scooping straight from the bag packs in noticeably more, and too much flour is the most common reason banana bread comes out dry.Cold butter for the streusel. Cut it in until you have pea-sized crumbs. Softened butter clumps together, melted butter turns to paste and sinks into the batter.Add the streusel right before baking. Sitting on wet batter, it starts absorbing moisture and works its way down instead of staying on top.Don't overmix the batter. Stop as soon as the flour streaks disappear. Lumpy is fine. Overmixing develops gluten and gives you a tough loaf with tunnels in it.Check at 50 minutes. A skewer should come out with a few moist crumbs, not clean. Clean means slightly overbaked. Tent with foil if the streusel browns before the loaf is done.Cool completely before slicing. Fifteen minutes in the pan, then out onto a rack. Warm banana bread slices gummy, and the streusel doesn't crisp into a proper lid until it's fully cool.Substitutions. Brown sugar for white gives a deeper, slightly moister loaf. Melted coconut oil or neutral oil works in place of butter. Only have two bananas? Add a couple of tablespoons of milk or yogurt to make up the difference.Muffins. Same batter and streusel in a muffin tin, 20 to 25 minutes at 350°F.Storage. Airtight at room temperature 2 to 3 days. Skip the fridge, it dries the loaf out faster than the counter. Freeze up to 3 months, ideally sliced with parchment between. Reheat a slice at 300°F for 5 to 10 minutes to bring the streusel back.