Preheat your oven to 350°F (175°C).
Grease a standard loaf pan with vegetable oil or line it with parchment paper.
In a large mixing bowl, combine flour, sugar, baking powder, baking soda, cinnamon, and salt. Whisk until well combined.
In another bowl, mix almond milk, vegetable oil, apple cider vinegar, and vanilla extract.
Pour the wet mixture into the dry ingredients and stir until just combined.
In a small bowl, mix granulated sugar and ground cinnamon for the swirl.
Pour half of the batter into the prepared loaf pan. Sprinkle half of the cinnamon-sugar mixture over this layer, then add the remaining batter on top. Sprinkle the rest of the cinnamon-sugar mixture and gently swirl with a knife.
Bake for about 50–60 minutes or until a toothpick inserted into the center comes out clean.
Let the loaf cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.