In a large bowl, whisk together flour, sugar, salt, soda, baking powder, and cinnamon.
In a medium bowl or measuring cup, whisk together the egg yolk, butter, buttermilk, and milk.
Add yolk mixture to dry mixture and stir gently until barely combined.
Give the egg white a quick whisk with a fork, then gently stir it into the remaining batter. Stop before the batter smooths out! Lumpy bumpy pancake batter is good!
Preheat an electric griddle to 375 degrees or heat a large non-stick pan over medium heat. Coat lightly with oil, if desired. Drop half cup fulls of pancake batter onto the preheated pan. Cook until bubbles start to appear on the exposed surface of the pancake. When bubbles begin to pop, flip pancake and cook for an additional 2-3 minutes or until browned. Keep finished pancakes warm in a single layer on a baking sheet in an oven preheated to 200 degrees.