1. Preheat oven to 350°. Grease a bundt pan with butter, then dust with 1 tsp. of the flour, tapping out excess, and set pan aside.
2. Sift the remaining 2 cups flour, sugar, cinnamon, baking soda, baking powder, and salt together into a large bowl. Add oil, applesauce, and eggs and stir until just combined. Add apples and nuts and gently stir into batter.
3. Pour batter into prepared pan and smooth out top with a rubber spatula. Bake until toothpick inserted in center comes out clean, about 1 hour. Set cake aside to cool for 15–20 minutes, then invert onto a cooling rack to cool completely