- Preheat and Prepare Pans: Preheat the oven to 350°F. Grease and flour two loaf pans (5 x 9-inch) and set them aside.
- Prepare Brown Sugar Mixture: In a medium bowl, stir together the brown sugar, cinnamon, and chopped pecans. Set aside.
- Mix the Batter: In a large mixing bowl, combine the dry cake mix, dry pudding mix, oil, water, and sour cream. The batter will be thick, so scrape down the sides of the bowl to ensure all dry ingredients are fully incorporated.
- Add Eggs: Add the eggs one at a time, mixing until each is fully incorporated.
- Assemble the Layers: Spread a layer of batter at the bottom of each prepared loaf pan. Use a knife or spoon to spread the thick batter evenly. Sprinkle a handful of the brown sugar pecan mixture over the batter. Repeat the layering process, ending with the brown sugar pecan mixture on top. Aim for two to three layers; it’s okay if the layers aren't perfect as you’ll swirl them in the next step. I usually make three thin layers of cake batter with brown sugar mixture on top of each layer and try to use half of the batter in each loaf pan.
- Swirl the Batter: Use a butter knife to gently swirl the batter. Insert the knife about ¾ of the way into the batter and make horizontal or vertical swirls, being careful not to scrape the bottom of the pan or overmix.
- Bake: Bake the loaves for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean.
- Cool: Remove the pans from the oven and place them on a cooling rack. Let the pistachio bread cool for about 30 minutes before loosening the sides with a spatula and turning out the loaves to cool completely.
- Serve and Store: Slice and enjoy! Store the bread wrapped in aluminum foil or in an airtight container.
This recipe makes two loaves, approximately 16 servings.