Beef balti with squash

Name: Beef balti with squash
Cuisine: Indian
Ingredients: 2 tbsp ghee or vegetable oil; 1 onion, thinly sliced; 1 large garlic clove, finely chopped; 2 tbsp balti spice mix; 1 tsp garam masala; Few curry leaves (optional); 450g Caledonian Crown sirloin steak, cut into 1½ cm cubes; 3 tomatoes, roughly chopped; 250ml beef stock; 2 tbsp tomato purée; 300g butternut squash, peeled, deseeded and cut into chunks; 1 pack Kitchen Guru Saffron Pilau Rice, to serve; Fresh coriander leaves, to garnish