Preheat your oven to 350°F (175°C) and prepare a greased and floured 9 x 5-inch loaf pan.

Whisk together the flour, sugar, baking soda, baking powder, salt, and cinnamon in a medium bowl.

In a separate bowl, mix the milk and lemon juice, let it sit for about 5 minutes, then add vegetable oil, vanilla extract, and eggs. Whisk until smooth.

Gradually fold the dry ingredients into the wet mixture until just combined.

Mix melted butter, brown sugar, and cinnamon in a small bowl for the swirl.

Pour half the batter into the loaf pan, layer with the swirl mixture, and gently swirl through the batter.

Add the remaining batter and top with the remaining swirl mixture. Swirl again.

Bake for approximately 50 minutes until golden brown. A toothpick should come out clean.

Cool bread in the pan for 5-10 minutes before transferring to a wire rack.