Sweet potato satay stew

Ingredients

• 1 onion
• 20ml of vegetable oil
• 2 cloves of garlic, finely chopped
• 2 small chunks of fresh ginger, peeled and chopped
• 1/2 teaspoon of cayenne pepper
• 600g of sweet potato, washed, peeled, and cut into cubes
• 1 tablespoon of mild or medium curry paste
• 300ml of passata
• 300ml of low-salt vegetable stock
• 200g of spinach leaves, washed
• 4 tablespoons of peanut butter
• fresh coriander to garnish
• black pepper