Preheat your oven to 425°F (220°C) with an oven-safe skillet inside.
In a bowl, whisk together flour, milk, eggs, sugar, lemon zest, and melted butter until smooth.
Gently fold in the blueberries.
Remove the hot skillet from the oven, add butter to coat it evenly, then pour in the batter.
Bake for about 20 minutes or until puffed and golden.
Serve warm with powdered sugar or your choice of toppings.
