Preheat the oven to 350F. Butter and flour every nook and cranny of a full sized 12-14 cup non-stick bundt pan.

In a stand mixer, cream the butter and brown sugar together until light and fluffy.

Beat in the eggs, one at a time, scraping down the bowl as you go, and then mix in the vanilla.

Sift or whisk together the dry ingredients.

With the mixer on a medium-low speed, add the dry ingredients to the wet, alternately with the sour cream, beginning and ending with the dry ingredients. Mix well with a silicone spoon to ensure everything is well combined.

Toss the nut mixture together with a fork.

Layer 1/3 of the batter into your prepared pan, top with 1/2 of the nut mixture, add another 1/3 of the batter, then the rest of the nut mixture, and finally the rest of the batter. Gently spread the batter across the top surface.

Bake for 1 to 1 1/2 hours. Check with the toothpick test, covering with foil if the cake seems to be browning too quickly. Check at one hour.

Let the cake cool on a rack for 10 minutes, then gently probe around the edges and neck of the pan to loosen the cake. Invert onto a plate or cooling rack.