Preheat the oven to 350 degrees. Grease and flour a 10-inch tube pan, bundt pan or any 10-inch baking pan.
Using an electric handheld or stand mixer fitted with the paddle attachment (or by hand if preferred), beat the butter and sugar until light and fluffy, about 4 minutes. Add the eggs one at a time, then add the vanilla and sour cream.
In a separate bowl, sift together the flour, baking powder, baking soda, and salt. With the mixer on low, add the flour mixture to the wet mixture and mix until just combined. Finish stirring with a spatula to be sure the batter is well mixed.
For the streusel, place the brown sugar, flour, cinnamon, salt, and butter in a bowl and pinch together with your fingers until it forms a crumble. You can also use a fork if preferred. Mix in the pecans.
Spoon half the batter into the pan and spread it out with a spatula. Sprinkle 3/4 cup streusel. on top of the batter. Spoon the rest of the batter in the pan, spread it out, and scatter the remaining streusel on top. Bake for 45 to 55 minutes or until a cake tester comes out clean.
Let cool on a wire rack for at least 30 minutes. If you baked it in a tube pan, carefully transfer the cake, streusel side up, onto a serving plate. If you've baked the cake in a 10 inch regular baking pan just serve it right from the pan
Whisk the confectioners’ sugar and maple syrup together, adding a few drops of water, if necessary, to make the glaze thick but runny. Drizzle the glaze over the cake with a small spoon. Serve at room temperature.