Preheat the oven to 350°F and prepare three 6 inch cake pans. Spray them with baking spray, add a parchment round, and fit with baking strips (if you have them).
In a large bowl, beat sugar, canola oil, eggs, sour cream, applesauce, and vanilla until well combined. Set aside.
In a medium bowl, sift together the flour, spices, baking powder, and baking soda. Add the salt. Whisk to combine. Remove 1 tablespoon of the dry ingredients and toss with the toasted walnuts in a small bowl. Set aside.
Add the dry ingredients to the wet and mix until just combined. Some specks of flour are fine. Add the carrots and walnuts. Gently fold until combined.
Place a scant 2 cups of cake batter in each pan. You will have nearly a cup of batter leftover. Bake for 38- 42 minutes, or until the cakes spring back when poked and are just starting to pull away from the edge of the pan.
Cool in the pans for 10- 15 minutes, then invert onto a cooling rack to cool completely.