Preheat oven to 350 degrees. Grease & Flour a 10" fluted Bundt Pan or 2 mini Bundt pans.Throughly chop Macadamia Nuts & mix well with other swirl ingredients. Set aside. Sift Dry Ingredients together & set aside.
Cream Butter & Coconut Oil together on high for 3 minutes, Beat in sugar & half of brown sugar and beat for 2 minutes. Add remaining brown sugar and continue beating for 2 minutes longer. Beat in eggs one at a time, blending well after each. Scrape down the sides of the bowl frequently to keep batter, even textured. Add Vanilla.
On low speed, alternately add Dry mixture in 3 additions with Sour Cream in 2 additions - begin & end with the flour mixture. Spoon half of the batter into the pan. Make a trench with the back of a spoon and generously sprinkle on the Macadamia mixture. Spoon over the remaining batter. Draw a thin metal spatula through the batter to swirl it in. Smooth the top of the batter with the spatula.
Bake cake for 55 minutes or until risen and a wooden pick inserted comes out cleanly (or with a few moist particles). The baked cake will pull away from the sides of the pan. Cool cake in the pan on a rack for 5 to 7 minutes. Invert the cake onto another rack (removing from the pan)and cool completely.