Slow-cooker red lentil soup

Name: Slow-cooker red lentil soup
Prep time: 20 min
Cook time: 4 h 10 min
Total time: 4 h 30 min
Cuisine: Asian, Indian
Ingredients: 9.20 gm olive oil; 1 brown onion, diced; 2 carrots, diced; 2 celery stalks, diced; 2 garlic cloves, thinly sliced; 4cm piece fresh ginger, peeled, finely chopped; 7.50 gm ground cumin; 3 tsp ground coriander; 375.00 ml red lentils; 1 litre vegetable liquid stock; Chopped fresh coriander leaves, to serve; Plain Greek-style yoghurt, to serve; Warmed garlic naan bread, to serve