Once you have removed the squash from the oven or microwave, check to see if it is cooked by sticking a knife into it. The knife should slide in easily. Flip the squash over with a spatula so that the cut side is facing up. (Be careful as it will be very hot!). Using a dinner fork, scrape the flesh of the squash moving gently around the shell fluffing up the strands of squash.Fold in the tomato, red onion, salt, pepper and cheese sauce until mixed. Serve with freshly grated parmesan.