In a medium bowl, stir together the milk, coconut oil (or butter), vinegar, maple syrup, and vanilla extract. Beat in the eggs. Don't worry if the melted coconut oil solidifies when combined with cold ingredients; just make sure everything is well mixed together.
Pour one cup of rolled oats (if not using pre-made oat flour) into a food processor or high-speed blender and process until it is ground well.
Add the baking soda, salt, and cinnamon to the oat flour. Pulse once or twice until well combined. If using pre-ground oat flour simply combine all the dry ingredients together in a bowl and stir together.
Add the oat flour mixture to the wet ingredients. Stir until just combined, being careful not to over-mix. It’s okay if there are a few lumps. The batter will be thin. It will thicken a bit while it sits but it should remain thin and pourable. If it thickens too much add a splash of milk to thin it out.
Heat a heavy cast-iron skillet or nonstick griddle over medium-low heat. Once the pan is hot, lightly oil the cooking surface with butter or coconut oil. Ladle or pour ¼ cup batter onto the pan for each pancake, being careful not to overcrowd the pan. Let the pancakes cook until small bubbles form on the tops and the underside is golden, about 3 to 4 minutes.
Once the bottom side has cooked sufficiently, flip and cook for another couple of minutes or so, until golden brown on both sides.
Serve the pancakes immediately or keep warm in a 200-degree oven. To serve, top pancakes with sliced nectarines, cherries, and a drizzle of maple syrup.
To freeze, allow pancakes to cool completely, then store in an airtight container in the freezer, separating each pancake with parchment paper or plastic wrap. When ready to eat, reheat in a warm oven or toaster.