Prepare the batter the night before you want to cook the pancakes.
In a large bowl whisk together the oatmeal, flour, baking soda, baking powder, cinnamon and nutmeg. Add the honey, eggs, vanilla, and buttermilk and mix until the batter is well-combined. Cover the bowl with plastic wrap and refrigerate overnight.
The next morning, briefly stir to combine. Heat an electric griddle or skillet over medium-low to medium heat. These pancakes need to cook for longer than traditional pancakes so they will burn if the heat is too high! If needed, spray the griddle or skillet with cooking spray.
Drop 1/4 cup of batter onto the preheated griddle or skillet. Let cook for 2-3 minutes until the edges are very set and bubbles are popping on the surface. Quickly slide a flat spatula underneath and flip the pancakes making sure they are set before flipping. Cook for another minute or so until they are cooked through. Serve warm with desired pancake toppings.