1. Heat the oil in a heavy frying pan and cook the onions over a very low heat, stirring occasionally, until they are very tender and golden in colour, approx 30 minutes. 2. Dissolve the tomato puree in the stock; add to the onions and season to taste. 3. Cook the pasta al dente; drain and pour into a serving dish with the knob of butter. 4. Stir in the hot onion sauce, toss with the cheese and serve. ---------------------------------------------------------------------------
Nutrition
Ingredients
