To make buttermilk, add apple cider vinegar to milk and set aside until ready to use, about 5 minutes.
In a large bowl, whisk together flour, sugar, baking powder, salt and cinnamon.
Whisk egg lightly in a medium bowl, add in milk mixture, vanilla, 2 tablespoons of melted butter and vanilla. Whisk until blended.
Pour the liquid mixture into the center of the flour and stir until combined, just until the ingredients start coming together, you will see lumps. Do not overmix. Allow to rest for 5-10 minutes.
Heat a griddle or fry pan/skillet, add some of the melted butter, when heated, (if using a fry pan/skillet) swirl the pan to cover the bottom evenly. Add ¼ cup of the batter into the fry pan/skillet and cook for about 2 minutes, until you see the bubbles forming on top and the edges start go get golden. Flip and cook for another minute. Transfer pancake to a serving platter or transfer them into a warm oven on a baking sheet without overlapping to avoid the pancakes to become limp.
Glazed Apples: Heat butter in a skillet over medium heat, once butter is hot, add diced apples and brown sugar, cook for 5 minutes, stirring occasionally. Then add maple syrup and cinnamon. Cook for another 2-3 minutes until apples are golden.
Garnish pancakes with apple glaze, and maple syrup. Option to add bacon and pecans.