Preheat oven to 350⁰ F /175⁰ C (325⁰ F/160⁰ C if using dark nonstick pan). Generously butter a 10-inch tube pan with a removable bottom.
Prepare the topping: melt the butter. Remove from the heat and cool to tepid. In a medium bowl mix flour pecans, sugar, cinnamon, baking powder and salt. Add flour mixture to the butter and stir till moist and crumbly.
Prepare the filling: pulse all ingredients of the filling in a food processor till combined.
Make the cake: whisk flour, baking powder, baking soda, and salt in a medium bowl. Set aside. In a mixer bowl beat the butter with a paddle attachment on medium speed until smooth and creamy 1-2 min. Slowly add sugar and beat to incorporate. Through the entire process of mixing scrape the bowl when necessary. Beat in eggs one at a time. Blend the vanilla. On low speed, alternate adding the dry ingredients and sour cream, adding the flour in pour parts and the sour cream in three parts.
Layer the cake. Spoon 2 generous cups of the batter in the prepared pan, smooth it over. Sprinkle about ½ cup of the filling. Repeat the layers, ending with batter layer. Run the knife around the pan two times, without lifting up the blade, spacing the circles about 1 inch apart. Smooth the top with the back of the soup spoon.
Layer the topping on the cake and lightly pressing it into the batter.
Bake for 70-75 minutes till the wooden stick come out clean. Let cool for an hour on a wire rack.
Make ahead: This cake keeps for up to 5 days at room temperature under a cake dome or could be frozen for up to 3 months.