Sweet Potato Crust Pizza

Name: Sweet Potato Crust Pizza
Prep time: 25 min
Cook time: 1 h 15 min
Total time: 1 h 15 min
Yield: 4 portions
Ingredients: 350 g dried chickpeas; 500 g water; 2 - 3 sweet potatoes; 1 tsp bicarbonate of soda; ½ - 1 tsp dried mixed herbs; 1 tsp fine sea salt; 1 garlic clove; 80 g onions; 20 g olive oil; 400 g tinned chopped tomatoes; 30 g tomato purée; ¼ tsp dried oregano; ¼ tsp fine sea salt; &frac18; tsp ground black pepper; 100 g Cheddar cheese, grated; 60 g pepperoni