In the first step, remove the vegetables from the freezer. Set aside to defrost slightly for about 15 minutes. Now, add the vegetables, flour, coriander, cumin, and cayenne to a food processor. Season well and then blitz to a rough paste. Add the sunflower seeds and sesame, then pulse to combine. Divide and shape the mixture into 4 equal patties. Add the patties to a lightly flour-dusted tray and then turn ‘em over in the flour to coat. Next, put in the freezer for about 10 minutes to firm up and then pop in the fridge while you get on with your vegan mayo.
In the next step, trim, roughly chop, and then add the chili and spring onions to a liquidizer. Peel and add the garlic, along with mustard, chickpeas, tomato paste, lemon juice, brandy, and a good pinch of pepper and salt. Blitz well to combine then, slowly pour in 4 to 5 tablespoons of extra virgin olive oil with the liquidizer still running until smooth and the same consistency as mayonnaise.
In order to make the onion rings, peel and slice the onion into rounds. Separate them into rings and then put them into a bowl with a pinch of salt and vinegar. Leave for about 5 minutes. Meanwhile, combine the baking powder and flour in a bowl, pour in the ale, and whisk slowly until thick, smooth, and coating the back of a spoon nicely.
In this step, place a medium, deep pan over high heat and then pour in the oil and allow to heat up. Drop a piece of bread into the pan to test if the oil is hot enough. If the bread floats to the surface, sizzles, and turns golden, it is about right. Now, drain the onions, dust a handful of them with flour until lightly coated, and then dip into the batter. Next, remove using a slotted spoon, allow any excess batter to drip off, and then slowly lower into the hot oil. Cook until golden and crisp, for about one minute, turning halfway with the slotted spoon. Transfer to a double layer of kitchen paper and repeat the process with the remaining onion.
Preheat your oven to 325 degrees F. Heat a splash of olive oil in a big frying pan over medium heat and then add the burgers. Cook until cooked through and golden, for about 10 to 12 minutes, turning halfway and pressing down with a fish slice to get them nice and crispy. Now, transfer to a baking tray and then pop in the hot oven while you prepare the remaining ingredients.
In the next step, finely shred the lettuce. Add to a big bowl with half of the vegan mayo. Mix well.
Slice the tomatoes and put on a plate lined with kitchen paper. Pick over the basil leaves and sprinkle over a little salt. Now, top with another piece of kitchen paper and pat lightly to remove any excess water. Next, slice the gherkins lengthways and then halve and destone the avocado. Cut into slices after you scoop out the flash, then squeeze over the lime juice.
In the last step, halve and toast the burger buns under the grill or on a hot griddle pan. Once ready, pile the sliced tomatoes and lettuce onto the burger bun bases. Now, pop a burger on top, snip over the cress and then layer over the gherkins and crispy onion rings. At the end of this step, add a good squeeze of ketchup to the tops of the burgers, place them on top, squeezing down slowly, then tuck in.