Preheat the oven to 350 degrees F (175 degrees C). Grease a 9-inch oven-safe skillet or baking dish with butter; set aside.
Combine almond milk, eggs, sugar, flour, melted butter, vanilla, and salt in a blender; blend until smooth. Pour into the prepared skillet; top with blueberries.
Bake in the preheated oven until center is set and top is lightly browned, about 40 minutes. Serve warm, dusted with confectioners' sugar.
