Blend eggs, milk, flour, vanilla, lemon zest, sugar, and salt in a blender until smooth and frothy. Let the batter rest for at least 30 minutes.
Preheat the oven to 425°F. Place a 10-inch oven-safe skillet on the middle shelf and heat it for 10-15 minutes.
Carefully remove the hot skillet from the oven and set it on the stove. Add butter and swirl until melted.
Toss the blueberries into the skillet, coating them in the melted butter.
Pour the batter over the blueberries and place the skillet back in the oven. Bake for 18-22 minutes until puffed and golden brown. Avoid opening the oven during baking.
Remove the skillet from the oven (the Dutch baby will deflate as it cools). Dust with powdered sugar and serve with lemon curd or maple syrup, if desired.
