Start by making the meatballs. Combine the lamb mince, breadcrumbs, blended onion, garlic, parsley, chilli flakes, cumin, salt, and pepper, being careful not to over mix.
Roll into equal sized balls, and pop into the fridge.
Preheat the oven to 200 C. Drizzle a tray with olive oil, arrange the meatballs, then into the oven for 20 minutes.
For the sauce, saute the onion, garlic, and chilli in a knob of butter. Once softened and fragrant, add the tomato and harissa paste. Stir through, cook for 2-3 minutes, then deglaze with the tomatoes, water, cumin, balsamic, brown sugar, salt, and pepper.
Leave to simmer on low for 20 minutes until thickened and darkened, adding more water if needed.
Add the cooked meatballs to the sauce, and leave to simmer for another 5 minutes.
Cook the pasta, and gently toss through the meatballs in sauce. Serve with crumbled feta and crusty bread.