In the bowl of a food processor, combine the toasted pecans, flour, granulated sugar, brown sugar, cinnamon, and salt. Pulse several times until well mixed and the pecans are broken down, about 5 to 6 pulses.

Pour melted butter over the mixture and pulse again for another 3 to 4 times until well incorporated.

Preheat your oven to 350°F (180°C) and grease eight 4-inch springform or cake pans, lining the bottoms with parchment paper.

In a large bowl, whisk together granulated sugar, brown sugar, buttermilk, eggs, melted butter, vegetable oil, vanilla extract, salt, and baking soda until blended.

Add the mashed bananas, whisking again to combine. Gradually add the flour, mixing until just incorporated.

Evenly divide the batter into prepared pans.

Sift cream cheese and granulated sugar in a stand mixer fitted with a paddle attachment. Beat on low speed until smooth and creamy.

Add the egg and mix until completely incorporated.

Divide cream cheese filling among the cake batter in the pans, smoothing the tops as best as possible. Sprinkle streusel over each cake.

Carefully place the pans in the oven and bake for about 25 to 35 minutes or until a skewer inserted into the center comes out clean.

Once baked, transfer the pans to a wire rack and cool until barely warm or at room temperature before removing from pans.