Cut the butter into small pieces and melt in a small saucepan over medium heat or in the microwave. Remove and cool.
Heat the griddle over medium heat.
Whisk together the eggs, buttermilk, flour, sugar, baking powder, cardamom, vanilla, baking soda, cinnamon, salt and melted butter together. Stir until you have a lumpy batter, but don't over mix.
Carefully wipe the griddle down with vegetable oil using a paper towel. Add a very small pat of butter to the griddle and swirl to melt. Once the butter is foamy, add the pancake batter using a 1/4-cup ladle. Flip the pancakes once you see a ring of bubbles around the edges, about 3 minutes. Cook the next side for about 2 minutes more.
Wipe the griddle clean and re-oil and butter between each batch. Repeat for the remaining batter. Serve immediately with Blueberry Syrup.
Add the syrup and blueberries to a small saucepan over medium heat. Simmer for 10 minutes, until slightly thickened. Smash a few of the berries with a wooden spoon against the sides of the pan. Serve over buttermilk pancakes.