Butternut squash casserole

INGREDIENTS

• 2 tbsp olive oil
• 1 onion , sliced
• 2 garlic cloves, crushed
• 1 tsp cumin seeds
• 1 tbsp paprika
• 225g sweet potatoes , cubed
• 1 red pepper , deseeded and chopped
• 1 butternut squash (about 550g/1lb 4oz), peeled and chopped
• 400g can chopped tomatoes
• 200ml red wine
• 300ml vegetable stock
• 75g bulghar wheat
• 4 spoonfuls Greek yogurt
• a little grated vegetarian cheddar cheese