Preheat oven to 220C. Place a 28cm-deep frying pan in the oven to heat.
Whisk eggs, milk, flour, vanilla seeds and a pinch of salt in a jug with a hand-held blender until smooth. Add butter to pan and swirl to coat surface, then pour in batter and bake until puffed and golden (15-20 minutes). Serve hot, dusted with sugar, and with berries, yoghurt and lemon halves to the side.