First of all I made the salad, because it's nicer if it has some time to chill before you eat it. I did take the mince out of the fridge though, to give it a chance to come up to room temperature.
Finely slice half a fennel bulb, half a cucumber and a bunch of radishes. Mix them up with chopped mint and parsley, salt and pepper, olive oil and a couple of capfuls of white wine vinegar (or lemon juice). Stash in the fridge while you make the burgers.
Finely slice some purple onion and pop it in a hot frying pan with a light sprinkling of sugar. Don't stir much, just leave them to caramelise. Mix the minced beef with a teaspoon or so each of soy sauce, worcestershire sauce, natural yoghurt and a sprinkling of chilli powder, cumin, salt and pepper, plus a small handful of chopped coriander. Once cooked, cool down the onions a bit and mix them in too. Form into patties and get the frying pan nice and hot.
Put the patties in to cook (hot, hot pan, and don't move them about) and slice your bread. While the bread is toasting, slice up some gherkins and a couple of thin slivers of mature cheddar.
Once it's toasted, put a dollop each of ketchup and mustard on one slice, topped with the cheddar, and some mayo and the gerkin slices on the other.
Portion out the salad and then lay the cooked burger patties on top of the cheese.
Fast. Naughty. Delicious.