Heat a saucepan of water and add the oil and salt. Cook the spaghetti according to packet directions and drain.
Melt butter in large saucepan over medium heat. Add onion and garlic and cook, stirring occasionally, for two minutes. Add soup, stock, seasoning salt and 1 1/2 cups of the grated cheese. Cook and stir until cheese melts and mixture is smooth. Add spaghetti and turkey or chicken. Mix well. Transfer to 2 litre baking dish and cover with foil.
Bake for 30 minutes or until hot and bubbly.
Remove foil. Sprinkle with remaining 1 1/2 cups cheese. Continue baking 2 minutes or until cheese melts. Sprinkle with parsley and capsicum.