Step 1

Stir milk and vinegar together in a bowl; set aside until milk "sours", about 5 minutes.

Step 2

Mix flour, white sugar, baking powder, baking soda, and salt together in a separate bowl. Whisk egg, 2 tablespoons melted butter, and 1 1/2 teaspoons vanilla extract into milk mixture. Slowly pour milk mixture into flour mixture while whisking constantly until batter is just moistened and evenly mixed. Lumps are fine.

Step 3

Combine brown sugar, 1/4 cup melted butter, and cinnamon in a small bowl. Place a 1-quart resealable bag into a glass or cup. Pour cinnamon mixture into the bag; refrigerate until filling is as thick as toothpaste, about 10 minutes.

Step 4

Mix 1/4 cup softened butter and cream cheese together in a microwave-safe bowl; heat in microwave for 40 seconds. Stir mixture with a whisk or fork until smooth. Continue heating in microwave and stirring until mixture is completely melted. Stir confectioners' sugar and 1/2 teaspoon vanilla extract into cream cheese mixture until icing is smooth.

Step 5

Heat a griddle or skillet over medium heat and spray with cooking spray. Pour about 2/3 cup batter into the center of griddle. Cook pancake until bubbles start to appear, 2 to 3 minutes. Cut 1 corner off the center of the bag with filling. Swirl filling over pancake, leaving enough space around edges that filling doesn't touch the griddle.

Step 6

Flip pancake and cook until other side is lightly browned, 2 to 3 minutes. Drizzle icing over pancake. Repeat with remaining ingredients, spraying the griddle with cooking spray between each pancake.