Mixed vegetable meatballs

Name: Mixed vegetable meatballs
Ingredients: 350 g celeriac chopped into cubes; 250 g swede chopped into cubes; 1 red onion finely chopped; 2 cloves garlic finely chopped; 2 large handfuls kale chopped; 1 tsp nutmeg finely grated; 1 tsp fresh thyme; Zest of 1 lemon and juice of 1/2; 1 large handful breadcrumbs; 1 egg; 1 handful Parmesan cheese; 1 medium white onion finely chopped; 1 clove garlic finely chopped; 1 tin quality chopped tomatoes; 1/2 tsp ancho chilli flakes (or normal but ancho give a lovely smokiness); Olive oil; Salt and pepper