Preheat oven to 425°F (220°C) and place a 10-inch cast iron skillet inside to heat.
In a blender, combine eggs, flour, milk, granulated sugar, vanilla extract, lemon zest, and salt.
Blend on high speed for 30 seconds until the batter is smooth and frothy.
Carefully remove the hot skillet from the oven and add the butter, swirling it until completely melted and bubbling.
Pour the batter into the center of the skillet immediately.
Scatter the fresh blueberries over the batter.
Bake for 18 to 20 minutes until the pancake is puffed, set, and golden brown.
Remove from the oven, drizzle with lemon juice, and dust with powdered sugar before serving.