Get a large pan on a medium heat and add a splash of olive oil. Once the pan is good and hot, add the mushrooms and thyme and season with salt and pepper. Fry on a good heat until the mushrooms have dried out and are slightly browned, then set to one side and leave to cool.
Next, drain the white beans and put them into a food processor with the dates, garlic, parsley, tahini and soy sauce. Pulse until you have a smoothish mixture, then transfer to a bowl and add the rice, breadcrumbs, lemon zest and the cooled mushrooms. Mix well, then put into the fridge for 10 minutes or so to firm up.
Once cooled, divide the mixture into 8 portions and shape into 8 patties. Place them on a baking tray lined with baking paper and pop into the fridge until needed. (This can be done the day before – and the burgers freeze well at this point.)
Preheat your oven to 230°C/fan 210°C/gas 8 and bake the burgers for 15 minutes, until nicely brown. If you like cheese on your burger, pop a slice on top a couple of minutes before they come out of the oven.
While your burgers are cooking, get your toppings ready. I go with avocado, tomato relish and the quick cucumber pickle above, plus a few spinach leaves. Hummus, grated carrot and sprouts is another favourite, but feel free to improvise and try it your own way. Once the burgers are golden, toast your buns and layer up your burgers. I like to serve them with the sweet potato fries. You can’t beat a burger and chips, and these ones are as healthy as they are tasty.