Put a large pan of water on to boil for your pasta.
Heat the oil in a large frying pan and add the onions. Cook on a medium heat for 3-4 minutes, stirring occasionally. Next add the garlic and red pepper and cook for 2 minutes. At this point your water should be boiling. Add the pasta and cook on a gentle simmer for 12-13 minutes.
Add the salmon to the pan (skin side down if it has skin) and turn the heat up to high. Pour in the tin of chopped tomatoes. Add the tomato puree, thyme and sugar. Give everything a gentle stir and when it starts to bubble, turn the heat down to medium - allowing the salmon to cook in the simmering sauce.
Whilst the sauce is simmering, use your spiralizer to spiralize the courgette/zucchini.
Check on your salmon. After about 5-6 minutes of simmering, turn the salmon over. At this point, if the salmon has skin, you can remove it using a pair of tongs and a fork. Break the salmon up a little bit to help it cook faster.
After another 5 minutes of simmering, move the salmon to one side of the pan, take the pan off the heat and very carefully (so you don't get splashed) use a hand blender to blend half of the sauce. Add the cream, mix and put back on the heat.
Add the courgette noodles to the pasta pan for the last minute of cooking, then drain and divide between four bowls.
Spoon the salmon and sauce on top of the spaghetti and serve with a sprinkle of grated cheese and chopped basil.
Any leftover salmon sauce can be cooled quickly, placed in a covering container and frozen. To reheat - defrost thoroughly at room temperature and re-heat until piping hot throughout either in a pan or in the microwave..Nutritional Information is per serving.