Lentil & cauliflower curry

Name: Lentil & cauliflower curry
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Cuisine: Indian
Ingredients: 1tbsp olive oil; 1 large onion chopped; 3tbsp curry paste; 1tsp turmeric; 1tsp mustard seeds; 200g red or yellow lentil; 1l low-sodium vegetable or chicken stock (made with 2 cubes); 1 large cauliflower broken into florets; 1 large potato diced; 3tbsp coconut yogurt; coriander chopped; lemon; brown rice to serve