Preheat oven to 375°F.

Place a medium cast iron skillet in the oven and let it preheat for about 5 minutes.

In a small bowl, mix the blueberries with 2 tablespoon of flour until well-coated; set aside.

In a medium bowl, mix together the remaining flour with the lemon zest, sugar, salt, baking powder and baking soda; set aside.

In another small bowl, melt 2 tablespoon of the butter and whisk together with the remaining liquid ingredients (buttermilk, milk, egg and vanilla). Add the liquid ingredients to the bowl with the dry ingredients; stir until just incorporated. (Tip: Take care not to overstir the batter.)

Fold half of the blueberries into the batter.

Remove the skillet from the oven and add the remaining 1 tablespoon of butter; brush evenly around bottom of skillet.

Using a spatula, spread the pancake batter evenly into the skillet. Gently press remaining half of the blueberries into the top of the batter.

Bake for 20-25 minutes, or until light golden brown.

Allow pancake to cool slightly; dust with powdered sugar and top with whipped cream and extra blueberries (optional) before serving.