Note: If using a stovetop griddle, I like to preheat mine in the oven for 10 minutes at 350ºF/175ºC for even heating.
In a measuring glass, stir the milk and vinegar together. It should curdle pretty quickly. This is the "buttermilk."
In a large bowl, add the flour, baking powder, baking soda, salt, brown sugar, cinnamon, and cardamom if using. Whisk well to combine.
In a medium bowl, mash the bananas with a fork but leave some small chunks for texture. To the mashed bananas, add the curdled buttermilk, vanilla, and melted butter. Whisk well to combine.
Pour the wet ingredients over the flour mix. Use a wooden spoon to fold the ingredients until just combined. Do not overmix—lots of lumps are fine.
Rest the batter for 5 to 10 minutes. But don't stir after resting, as the batter will lose air bubbles and turn out less fluffy. While the batter rests, start preheating the pan.
For cast iron or carbon steel instructions, see Note 5.
Heat a nonstick frying pan over medium to medium-low heat for several minutes (see Note). Add 1 teaspoon coconut oil. Allow to heat ~30 seconds. Test to see if the pan is hot enough by adding a droplet of water—if it sizzles and dances, it’s ready.Add ⅓ cup (80 to 90g) pancake batter to the pan, using a flexible spatula to get the batter out of the cup.After the first 30 seconds, swirl the oil in the pan around the edges of the pancake. Cook for a total of 2 to 2 ½ minutes, or until the edges start to dry out and some bubbles appear on the surface.Flip and cook on the second side for 1 to 2 minutes, swirling any remaining oil around the edges again. You may need to lower the heat to medium-low. Repeat with the remaining batter, adding a teaspoon of oil to the pan to preheat per pancake before adding more batter. You will likely need to lower the heat throughout cooking to prevent burning.
To keep pancakes warm, add to a wire rack-fitted sheet pan in the oven at 200ºF/95ºC until ready to serve.
Serve pancakes with maple syrup and fresh sliced bananas, if desired.