First, cut the onion in cubes, cherry tomatoes into halves, smoked salmon into thick (3cm width) and open the can of tomato purée. Set aside all ingredients.
Heat olive oil in pan and fry the onion for 6-7mins until softens. Add thyme and continue frying for 3mins until fragrant. Stir in tomatoes and fry for another 5mins until oil turns slightly red.
Oil should look like this colour before we move into the next step. Separately, boil the spaghetti (approx 8mins for al-dente texture)
Add the tomato purée and allow to simmer for 10-15mins. Add salt & pepper to taste. It should taste slightly sour when served later, so don't worry & don't over add the salt.
Add the cream & continue to simmer for 3mins. Thicken the sauce with flour & milk mix. As a final step, add the smoked salmon. Stir lightly and slowly so the fish don't break.
Place spaghetti in a bowl & pour the sauce over the dish. Serve hot.