Coarsely grate the onion, then put it in a large mixing bowl. Pop the crackers into a sealed sandwich bag and bash them with a rolling pin until fairly fine, then tip into the bowl with the parsley, parmesan, egg, minced meat and a tiny pinch of salt and pepper.
With clean hands, scrunch and mix everything together until well combined. Halve the mixture, then divide each half into four equal-sized pieces. Wet your hands, then pat and roll each piece into burger-shaped patties, roughly 2-cm thick.
Place the burgers onto a lightly oiled baking tray, pat with a little more olive oil, cover with cling film and pop in the fridge for 30 minutes to firm up.
Place a large frying pan on medium heat. Once hot, add the burgers and lightly press down on them with a fish slice so they’re in full contact with the pan. Cook for 3 or 4 minutes on each side, or until they are to your liking.
Meanwhile, halve and toast the burger buns. Serve your burgers in the buns, piled with your favourite toppings, and with the smashed salad on the side. Delicious served with baked sweet potato wedges.