Sausage ragu

Name: Sausage ragu
Prep time: 5 min
Cook time: 45 min
Total time: 50 min
Cuisine: European, Italian, Mediterranean
Ingredients: 3 tbsp olive oil; 1 onion finely chopped; 2 large garlic cloves crushed; ¼ tsp chilli flakes; 2 rosemary sprigs, leaves finely chopped; 2 x 400g cans chopped tomatoes; 1 tbsp brown sugar; 6 pork sausages; 150ml whole milk; 1 lemon zested; 350g rigatoni pasta; grated parmesan and ½ small bunch parsley, leaves roughly chopped, to serve