15 to 20 minutes
1 hour 15 minutes
For Streusel Topping: Preheat oven to 350ºF with rack in middle. Spread pepitas on a baking sheet and bake until lightly toasted, about 5 minutes. Remove from oven and let cool, then coarsely chop. In a bowl, mix cooled pepitas with sugar, poppy seeds and salt, until sugar is incorporated. Stir in butter. Set aside. (Leave oven on.)
For Banana Bread: Grease a 9×5-inch loaf pan with butter and dust with flour, tapping out any excess.
Stir together bananas, fairlife ultra-filtered milk and vanilla in a medium bowl. In a large bowl, whisk together flour, espresso, baking powder, baking soda and salt.
Using an electric mixer, beat butter and sugar on medium speed in another large bowl until light and fluffy, about 5 minutes. Add egg and beat until combined. Add banana mixture and beat until combined. Add dry ingredients in 2 additions, beating on low after each addition and scraping down sides of bowl as necessary until fully incorporated. Transfer batter to prepared pan and smooth top with spatula. Sprinkle with streusel topping.
Bake, rotating once halfway through, until sides are starting to pull away from pan, and a tester inserted into center of bread comes out clean, 1 hour to 1 hour 10 minutes. Cool in pan on a wire rack, 15 minutes. Run a butter knife around edges of loaf, then carefully invert onto a plate (some streusel will fall off; you can sprinkle it back on). Invert back onto wire rack and let cool completely before slicing.
Note: To quickly ripen bananas before baking, bake them unpeeled on a baking sheet, at 250ºF, until soft, 15 to 20 minutes. Let cool before peeling.