Cold Spaghetti Salad Recipe from Italy

Ingredients

• 1 lb (454 g) of spaghetti
• 1 can (15 oz (425 g)) of tomato sauce with bits
• 1 bottle (8 oz (227 g)) of italian salad dressing
• 1 small red onion , thinly sliced and separated into rings
• 1 can (4 oz (113 g)) of sliced button mushrooms , drained
• 1 can (4 oz (113 g)) of sliced ripe olives , drained
• 0.25 cup of chopped fresh parsley