Combine milk with vinegar in a medium bowl. Set aside for about 5 minutes to let the milk “sour”.
Combine flour, sugar, baking powder, baking soda, and salt in a large mixing bowl.
Whisk in egg and melted butter into soured milk.
Pour the flour mixture into the wet ingredients and whisk until lumps are gone.
Make the cinnamon swirl mixture in a separate bowl by combining all ingredients. Use either a squirt bottle (ketchup type bottle), or bag with corner snipped off.
Scoop pancake batter in small circles on heated pan/griddle. Immediately add the cinnamon swirls.
Cook the pancakes until small bubbles develop on top of pancake. Flip over using a spatula and cook for an additional 30 seconds. Serve!
Notes
*We just put a thin layer of butter on them to keep them moist, syrup may take away from the cinnamon swirl flavor. **If cinnamon mixture is too thick to drizzle, add milk to thin it out allowing it to pour on better