Mix together 1 cup of milk and 1 tablespoon of vinegar in a small bowl and let it sit for 5 minutes.

In a large mixing bowl, combine 1 cup of flour, 2 tablespoons of sugar, 1 teaspoon of baking powder, 1/2 teaspoon of baking soda, and 1/4 teaspoon of salt. Whisk to blend.

In a separate bowl, whisk the soured milk, 1 egg, and 2 tablespoons of melted butter until smooth. Combine with dry ingredients.

In a small bowl, mix 1/4 cup of brown sugar, 1 tablespoon of melted butter, 1 teaspoon of cinnamon, and 1 tablespoon of additional flour until thick paste forms.

Heat a non-stick skillet on medium. Pour 1/4 cup of batter for each pancake, drizzle with cinnamon swirl and cook until bubbles form.

Flip the pancakes and cook for an additional 30 seconds until golden brown. Keep warm while repeating with remaining batter.

Serve pancakes topped with maple syrup, powdered sugar, or butter.