Preheat oven to 350°F. Generously grease and lightly flour a 9x5-inch bread pan. Alternatively, line the pan with parchment paper.
In a large bowl, beat together the butter and sugar until light and creamy. Add in the eggs and vanilla. Beat to combine.
In a separate small bowl, mash the bananas thoroughly with a fork. Stir in the well-mashed bananas and Greek yogurt into the bread batter and mix until combined.
In another bowl, combine the flour, baking soda, and salt. Mix.
Combine wet and dry ingredients and mix until just combined. Don’t over-stir the batter.
Cinnamon Swirl: In a separate small bowl, stir together the granulated sugar and ground cinnamon. Pour half the bread batter in the prepared pan and evenly sprinkle the swirl ingredients on top. Pour the rest of the bread batter on top and smooth the top of the bread with a table knife.
Streusel: Melt the butter in the microwave, then let stand at room temperature until cooled (don’t add hot butter to the streusel—it will make it greasy). In a separate medium bowl, whisk together flour, brown sugar, cinnamon, and salt. Add the cooled melted butter and mix (knead with hands if needed) until the streusel is evenly combined and forms small clumps. If clumps aren’t forming or the streusel is too wet, add more flour, 1 tablespoon at a time. Sprinkle the streusel mixture evenly over the banana bread batter. Do not press the streusel into the batter. Use all the streusel (yes, it’s a lot).
Bake for 60–70 minutes or until a toothpick inserted in the center comes out clean or with a couple of moist crumbs.
Allow to cool for 10–15 minutes before running a table knife along the edges of the loaf and inverting the loaf onto a wire cooling rack.
Video
Notes
Storage: This bread stores 1–2 days at normal room temperature (wrapped tightly/stored in an airtight container). After 3–4 days, this bread is more prone to molding because of the ingredients used and the overall moistness of the bread.