Falafel burger with hummus

INGREDIENTS

• 250g/9oz chickpeas
• 1 medium onion
• 2 cloves garlic
• 2 tsp ground cumin
• 2 tsp ground coriander seed
• 6 tbsp chopped parsley
• ½ tsp chilli powder
• 2 rounded tbsp plain flour
• 1 tsp salt
• Oil for deep fat
• 125g/4½oz hummus
• 2 tbsp extra virgin olive oil
• 1-2 tbsp lemon juice
• 1 tbsp tahini
• 4 large rolls (or hamburger buns
• 1 fat tomato
• 1 red onion
• 4 leaves butter lettuce
• or fries, or sautéed potatoes salad