Preheat the oven to 350°F (180°C, gas mark 4).

Lightly coat an 8 × 4-inch loaf pan with nonstick spray.

In a medium bowl, combine the vinegar and soymilk.

Let it sit to curdle and form a buttermilk-like consistency.

In a small bowl, mix 1 teaspoon cinnamon with 3 tablespoons (36 g) Sucanat to create the cinnamon-sugar topping.

Set aside.

In a large bowl, combine the oats, flour, remaining 1½ teaspoons cinnamon, remaining 5 tablespoons (60 g) Sucanat, baking powder, baking soda, cornstarch, and salt.

Add the oil, vanilla, and applesauce to the buttermilk mixture and stir to combine.

Gently fold the wet ingredients into the dry ingredients, being careful not to overmix.

Pour half the batter into the prepared loaf pan.

Sprinkle half of the cinnamon-sugar mixture evenly over the batter.

Pour the remaining batter on top and sprinkle the rest of the cinnamon-sugar mixture evenly over it.

Bake for 35 minutes, or until a toothpick inserted into the center comes out clean.

Place the loaf on a wire rack, still in the pan, for about 15 minutes.

Then transfer the loaf directly to the rack and let it cool completely before slicing or storing.