Heat the oil in a large stock pot or pan over medium heat and fry the onion until soft, about 6 minutes.
2 Tbsp vegetable oil, 60 g onion, finely diced
Add the celery, carrot, and garlic and cook for a couple of minutes.
1 celery stalk, finely diced, 150 g carrots, peeled and cut in 1-cm (½-inch) thick semi-circles, 3 garlic cloves, grated
Stir in the flour until the vegetables are coated all over.
2 Tbsp plain all-purpose flour
Add the stock, chopped tomatoes, tomato puree, and Italian seasoning. Bring to the boil, then lower the heat and stirring from time to time, simmer uncovered until the carrots are soft, about 15 minutes.
1 litre vegetable stock, 800 g canned chopped tomatoes, 2 Tbsp tomato puree, 1 tsp Italian seasoning
Add the tortellini to the pan and cook until the pasta is done, about 10 minutes.
300 g fresh tortellini of choice
Stir in the spinach and cook for a minute or so until wilted.
1 generous handful of baby spinach leaves
Stir in the cream and parmesan.
250 ml cream of choice (single, soya, or half-and-half), 50 g freshly grated parmesan-style cheese (optional)