Corn split pea chowder

Name: Corn & split pea chowder
Ingredients: 200g dried yellow split peas; 3 celery sticks (about 160g), sliced; 1 thyme sprig, plus 1 tbsp thyme leaves; 2 onions (350g), halved and sliced; 1 tbsp rapeseed oil; 50g ginger, finely grated; 2 red chillies, deseeded and sliced; 3 garlic cloves, chopped; 1 large green pepper, chopped into small pieces; 1 potato (about 215g), unpeeled, cut into 1-2cm pieces; 2 tbsp vegetable bouillon powder; 320g frozen sweetcorn; 150g coconut yogurt