Bombay chilli cheese toastie

Name: Bombay chilli cheese toastie
Cook time: 30 min
Total time: 30 min
Cuisine: Indian
Ingredients: 300g potatoes boiled until tender, peeled and diced; 1 tsp (see cook’s notes below) chaat masala; ½ green pepper finely chopped; ½ red onion finely chopped; (a farmhouse loaf or bloomer is good for this) 8 slices soft white bread; softened butter; 8 slices emmental; 1 tbsp pistachio kernels soaked in just-boiled water for 20 minutes; 100g mint leaves; 50g coriander leaves; ½ lemon juiced; 1 green bird’s-eye chilli (add 1 more if you like it spicy); ¼ red onion finely chopped; 3cm chunk ginger chopped; a pinch caster sugar