Preheat the oven to 425°F. Line a 12-cup muffin pan with liners, or lightly coat the pan with nonstick spray. If you’re using liners, give them a quick spray as well to help prevent the muffins from sticking.
In a medium bowl, whisk together the 2 cups (250g) all-purpose flour, 2 teaspoons ground cinnamon, 1½ teaspoons baking powder, 1/2 teaspoon baking soda, and 1/2 teaspoon salt.
In a separate large bowl, whisk the 1/2 cup melted coconut oil (or vegetable oil/avocado oil), 1/2 cup (100 grams) white sugar and 1/4 cup (50 grams) brown sugar until well combined. Add the 2 large eggs, 1 teaspoon pure vanilla extract, and 1 cup (226g) unsweetened applesauce, and whisk until smooth.
Add half of the dry ingredients to the wet mixture and gently stir until just combined. Add the remaining flour mixture and fold with a rubber spatula or wooden spoon until no dry streaks remain. Be careful not to overmix.
Divide the batter evenly among the muffin cups. They will be almost full.
In a small bowl, stir together the 2 tablespoons granulated sugar or turbinado sugar and 1/2 teaspoon cinnamon, then sprinkle the mixture generously over each muffin.
Bake for 5 minutes at 425°F. Without opening the oven door, reduce the temperature to 350°F and continue baking for 14–16 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool in the pan for a few minutes, then transfer them to a wire rack to finish cooling.