In a large bowl, whisk together the Bisquick mix and baking soda. Whisk the egg, vanilla, and buttermilk in a separate bowl.
Add the buttermilk mixture to the Bisquick mixture and stir until moistened. This will create a thicker batter than another basic pancake recipe.
Scoop about ¼ cup of batter on to a griddle heated to 350-375 degrees and greased with melted butter or cooking spray, for each pancake.
Cook the pancakes for 2-3 minutes until bubbles begin to form and pop, then flip and cook the other side for 2-3 more minutes until golden brown.
Buttermilk Syrup: Heat the butter, sugar, and buttermilk in a saucepan over medium/high heat until the butter has melted and the sugar has dissolved. Remove from heat and stir in the vanilla and baking soda. Serve over the top of Bisquick Buttermilk Pancakes.