Masala meatball curry

Name: Masala meatball curry
Ingredients: 2 garlic cloves; 1 red chilli, deseeded; 1 thick slice white bread; small pack mint leaves, reserving some to serve; 400g lamb mince; 1 egg, lightly beaten; 1 tbsp vegetable oil; 1 large onion, roughly chopped; 1 tbsp masala curry paste; 400g can chopped tomato; 400ml lamb stock; 100g baby spinach leaves; cooked basmati rice and cucumber & mint raita, to serve (optional)