Start by searing the lamb to give it a good rich flavor. To do this, heat oil in your pan to a high heat and quickly cook the meat a few pieces at a time.
Next, cook the vegetables until soft and then return the lamb to the pan with the passata and water and bring to the boil before adding all the remaining ingredients.
Once it comes out of the oven, use a wooden spoon to break up the lamb a little to create a nice thick sauce.
Serve it over pasta (I like rigatoni for this dish, but parpadelle is another popular option).