Place the chickpeas, chopped onion, crushed garlic, chopped basil and tomatoes in a food processor with the salt and a generous grinding of pepper. Blitz until everything is very finely chopped and clumping together.
Stir in the ground almonds then pop the mix in the fridge for half an hour to make it easier to shape.
Divide the mixture into four equal parts; shape each one into a ball then flatten into a patty.
Place a frying pan with a drizzle of olive oil over a medium-low heat and add the patties. Cook for about four minutes per side until nicely browned then serve in a toasted burger bun with grilled halloumi, guacamole, lettuce and salsa.
Cut the ends off the onion and peel off the skin. Cut it into rings about 1cm wide. Separate out the rings and place them in a wide bowl. Mix together the buttermilk and milk and pour it over the onion, pressing it down to make sure that it is covered. Leave to soak at room temperature for about an hour.
In a wide, shallow bowl mix together the 100g plain flour, the salt and the cayenne pepper.
In a separate bowl mix together the cornflour, the 50g plain flour, the cajun seasoning and salt. Gradually whisk in the lager to form a smooth batter.
Half-fill a large saucepan with the oil and heat until it reaches 180C/350F on a thermometer (or until a piece of bread crisps in 20-30 secs) or heat a deep fat fryer to 180C/350F.
Drain the onion rings then coat them in the seasoned flour. Dip each ring in the batter and fry for 3-4 minutes until crisp, just do a few at a time so you don't overcrowd the pan. Drain on kitchen paper and sprinkle with salt then serve.