Preheat and prepare pan. Position a rack in the center of your oven and preheat the oven to 350°F (177°C). Spray a 9x5 loaf pan with cooking spray, or line with parchment paper and then spray with cooking spray.
Combine dry ingredients. In a mixing bowl, whisk together all-purpose flour, sugars, baking powder, baking soda, cinnamon, nutmeg and salt. Set aside. 2 cups (240 g) all-purpose flour ½ cup (100 g) granulated sugar ½ cup (107 g) packed light brown sugar ½ teaspoon baking powder 1 teaspoon baking soda ½ teaspoon salt 2 teaspoons ground cinnamon ½ teaspoon ground nutmeg
Combine wet ingredients. In a second mixing bowl, whisk together eggs, applesauce, buttermilk, and oil. 2 large eggs ¼ cup (60 ml) buttermilk ¼ cup (60 ml) neutral-flavored oil 1 cup (255 g) applesauce
Combine wet and dry ingredients. Add the dry ingredients to the wet ingredients and mix together with a spatula or wooden spoon just until just combined. Do not overmix.
Bake. Bake in a preheated 350°F (177°C) oven for 50-60 minutes until a toothpick inserted into the middle of bread comes out clean or with a few moist crumbs clinging to it (no wet batter) and top springs back to the touch when lightly touched. Remove from the oven and cool completely in the pan on a wire cooling rack.