• 2 tbsp olive oil, plus extra to fry the burgers
• 1 small onion, finely chopped
• 2 garlic cloves, crushed
• 1 tsp coriander powder
• 1 tsp cumin powder
• 1 tsp chilli powder
• 1 tsp pink peppercorns, crushed
• 600g/1¼lb pork mince
• 200g/6½oz pork fat, minced
• 1 tbsp chopped fresh sage
• 2 free-range eggs
• salt and freshly ground black pepper
To assemble the burgers
• 4 rings fresh pineapple
• 8 thin slices gruyère
• 2 hamburger buns
• 50g/2oz rocket
• 2 vine-ripened tomatoes
• 100ml/3½fl oz mayonnaise
• 1 tsp chillies, finely chopped
• onion rings, to serve