Fry off the onion and mushrooms in some extra butter / vitalite until soft

In another pan make a white sauce by melting the vitalite and adding the flour to make a paste then slowly adding the rice milk stirring all the time while bringing to boil. You may need more or less milk

Add the onion and mushroom to the sauce then using a hand blender blitz half the mixture so you have a smooth sauce with some chopped veg still there

Add the chicken, peas, salt and basil and let simmer a few minutes til chicken is cooked through

For an adult version make the sauce as in steps 1-3 with a half tsp of chicken or vegetable bouillon powder stirred in and pour over cooked chicken breasts and serve with boiled rice and peas