In a small bowl, whisk together the flour, cardamom, baking powder, baking soda, and salt. Set aside.
In a large bowl, combine the butter, buttermilk, egg, vanilla, and sugar. Stir until well blended.
Add the dry ingredients to the wet ingredients and stir gently with a wooden spoon, being careful not to over mix the batter. It should still be a bit lumpy. Let the batter sit for 10 minutes.
Lightly grease a griddle or skillet with butter and heat to medium heat. Scoop ⅓ cup of batter onto the griddle or skillet for each pancake. Let the pancakes cook for about 2 minutes, until they puffs up slightly and bubbles begin to appear on the surface of the batter. Then top each pancake with a handful of blueberries. Cook for another minute or two, just until the bubbles begin to pop. Then flip each pancake using a spatula and allow to cook for another minute, or until both sides are golden brown.
Serve the pancakes with additional butter, if desired, and maple syrup.