To make the caramelised onions, heat olive oil in a medium pot on medium heat. Cook onion for 7-8 minutes, stirring often, until starting to caramelise. If at any time the onion is sticking to the bottom of the pan and burning, add 1-2 tablespoons of water, stir and it should unstick. Stir through balsamic vinegar and honey, cook a further 1-2 minutes then remove from heat and season to taste with salt and pepper.
While onions cook, make the lentil and cashew burgers. Crush cashews with a rolling pin (or in a food processor) and add to a medium bowl with half the lentils, tahini, onion, egg, lemon zest, soy sauce, spices and parsley. Mash well with a potato masher, until mixture has the consistency of hummus. Season with salt and pepper and stir through remaining lentils, breadcrumbs/ground almonds and flour.
Divide burger mixture into four and shape into patties, about 1cm thick. Set aside on a plate and dust each with a little flour.
Heat half of the oil in a large non-stick fry-pan on low-medium heat. Cook lentil burgers, two at a time, for 2-3 minutes each side, until golden brown and cooked through. You may need to add ½ teaspoon more oil when you flip the burgers, to help the crust crisp up. Set burgers aside to drain on a plate lined with paper towels.
In a small bowl, roughly mash avocado with lemon juice and season to taste with salt and pepper. In another small bowl, mix yoghurt/sour cream and chipotle sauce.
To serve, top each lentil and cashew burger with tomato, cucumber, avo smash, caramelised onions and place on a bed of lettuce. Drizzle with creamy chipotle and sprinkle with pickled gherkins and jalapenos.