One of Annabel Karmel's sounds LOVELY to me, but as my DS is allergic to milk, we can't add the cheese:
3 ounces courgette (zucchini), peeled and diced
1 oz butter
3 medium tomates, skinned, deseeded and chopped
1 oz cheddar cheese
Cook pasta. Saute the courgette in the butter for about 5 minutes. Add the tomates and cook over low heat for 5 minutes. Remove from heat, stir in the cheese until melted. Puree in a blender and stir in the pasta.
Super easy! She does have quite a few other pasta sauce recipes, but they do all call for some sort of cheese, so I am still working on adapting them to add some extra flavour and the texture it might need to make them sutiable for MPI.