So far so good. But this wasn't enough for me, I wanted my own unique twist, something that would really pack a flavour. I considered a few different options, until I settled on a sort of "Tex-Mex" theme... hot chili tomato sauce on one side of the burger, and guacamole on the other.
I made the spicy sauce by frying chopped onion and chili, adding black pepper and cumin, then chucking in some tomato puree, ketchup, Tabasco, and chopped coriander.
The burger was made by sandwiching a big lump of cheese (Cheddar and Gouda) in between two large burgers, and pressing the edges together while it cooked. I squashed the whole thing down as much as possible, but it was still a gargantuan burger. I actually had to put it in the oven to make sure it was cooked through.
This monstrosity - placed between a toasted bun with generous dollops of guacamole and the spicy tomato stuff - is a whole meal in itself. No chips or onion rings necessary, just a comfy chair and a nice cold beer.