In another bowl, combine the ground flaxseed and water. Let it sit for 5-10 minutes to thicken.
2 tablespoons ground flaxseed, 1/3 cup water
Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan with non-stick spray and line it with parchment paper.
In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.
2 cups all-purpose flour, 2/3 cup organic granulated sugar, 3 teaspoons baking powder, 1 teaspoon baking soda, 1/2 teaspoon salt
In a separate measuring cup, stir together the non-dairy milk, canola oil, apple cider vinegar, and vanilla extract. Add the thickened flaxseed mixture to the wet ingredients and mix well.
3/4 cup unsweetened non-dairy milk, 1/3 cup canola oil, 1 tablespoon apple cider vinegar, 1 tablespoon vanilla extract
Pour the wet mixture into the dry ingredients and stir until just combined, being careful not to overmix.
Pour half of the batter into the prepared loaf pan and spread it evenly with a spatula.
Sprinkle 2/3 of the cinnamon sugar mixture evenly over the batter, followed by 2/3 of the chopped apples.
Pour the remaining batter over the apple layer, then top with the rest of the cinnamon sugar mixture and the remaining apples.
Use a knife to swirl the cinnamon sugar mixture into the batter by creating a wavy or "S" shape pattern.