Step 1

Adjust oven rack to middle position and preheat oven to 350°F. Grease pan with butter.

Step 2

For Streusel: In a medium bowl, combine pecans, dark brown sugar, sugar, cinnamon, and flour and stir to combine. Add flour and melted butter and mix until has the texture of wet sand. Set aside.

Step 3

For Cake: In a medium bowl, whisk together flour, baking powder, baking soda, and salt; set aside. In the bowl of a stand mixer fitted with a paddle attachment beat butter and sugar until fluffy, about 3 minutes. Add eggs and egg yolk and beat to combine. Add vanilla and yogurt, then dry ingredients, beating until just mixed together. Gently fold in bananas with a spatula.

Step 4

Pour batter into pan and smooth top. Cover with pecan mixture. Bake until a tester inserted into the middle of the cake comes out clean, 50-60 minutes. Let cool then release from springform pan and serve.