Cheesy prawn bake

1) Preheat oven to 230°C, Gas 8.
2) Shell and cut the eggs into chunks.
3) Melt the butter in a saucepan and stir in the flour. Cook, stirring, for 1 minute.
4) Remove from the heat and gradually add the milk. Bring to the boil, stirring until thickened.
5) Stir in salt, pepper, mustard and dill.
6) Layer the prawns and eggs in an ovenproof dish.
7) Pour over sauce and sprinkle with grated cheese.
8) Bake for 15-20 minutes, until golden and bubbling.