To make the streusel, combine the pecans, butter, brown sugar, and spices in a small bowl.
To make the cake, whisk together the flour, baking powder, baking soda, and salt in a medium bowl.
Beat the butter, granulated sugar, and brown sugar with an electric mixer on medium-high until light and fluffy, 2 - 3 minutes. Beat in the eggs and vanilla, scraping down the sides twice.
Reduce mixer speed to to low and add the flour mixture and sour cream in alternate additions.
Spread half the butter in the bundt pan and top with half the streusel; repeat.
Bake, rotating once, until golden brown and a toothpick inserted in the center comes out clean, 45 - 50 minutes.
Cool for 10 minutes in the pan. Invert onto a wire rack to cool completely.
Sprinkle powdered sugar over the top of the cake and serve.
Notes
*To make the recipe gluten-free, replace the flour with ¾ cup white rice flour, ¾ cup tapioca flour, ½ cup potato starch, and 1 teaspoon guar gum
Recipe by Premeditated Leftovers™ at https://premeditatedleftovers.com/?p=16962