Ham Pasta Bake

6 cups Ham, cubed
8 cups frozen peas & corn
4 onions finely chopped
2kg uncooked pasta
2 tsp salt
350g cheese grated, divided in two
200g butter
200g flour
2.5 litres milk
4 tbsp stock powder (chicken)
2 tbsp hot mustard
1 tbsp nutmeg
1/2 tbsp pepper
Cook pasta in a large pot of boiling salted water. In a separate pot melt the butter, add the flour and mix well over the heat, cook until the mixture goes mostly white and foamy. While stirring, add the milk by degrees (500ml at a time). Continue to stir constantly until the white sauce comes to the boil. Add the chicken stock, nutmeg and mustard.
Cook the peas corn and onion in the microwave untill completely hot. Combine the vegetables and white sauce, add the cubed ham and half the grated cheese.
In a baking dish put 3/4 of the cooked pasta. Spread the ham mixture over the pasta evenly. Spread the remaining pasta over the ham. Cover the pasta with the second half of the grated cheese. Sprinkle with a little extra nutmeg.
Bake on med-high for 20-25minutes.