Tuna with Onions and lardons

I love tuna steak and I am always looking for new ways to cook it. I found this recipe in a great book called 'Fish' by Sophie Grigson and her partner William Black. She's the daughter of famous cookbook author Jane Grigson who's English Food is the seminal book if you want to make traditional, old fashioned English food. The book is loaded with wonderful recipes, new ideas on ways to cook fish but it also talks about the history of fish as a food in Britain, why it waxed and waned in public opinion over the centuries and discusses sustainable fishing practices. It tells you how to buy, store and prepare all types of fishes and crustaceans. The only hard thing for me is living on the East coast of the U.S., many of the fishes they mention are not commercially available here. I've learned to substitute.

2 Pieces of tuna steak, cut a good 2.5 cm (1 inch) thick, weighing about 175 - 225g (6 - 8 oz) each
60 - 85g (2 - 3 oz) lardons, or streaky bacon (I use thick cut bacon)
60g (2 oz) butter (i use a bit less)
1 onion sliced
1.5 TBS red wine vinegar
salt and pepper

Season the tuna with salt and pepper. If you are using bacon, make the lardons. Cut the bacon into little sticks about 1 inch long (rather like match sticks).
Melt a third of the butter in a frying pan and add the onion. Cook over medium heat until it begins to brown, then add the lardons and continue cooking until the onion and bacon are well browned. Draw off the heat.

Instead of using a separate pan as they do, I just put the onions and lardons on a plate and then using the drippings in the pan (rather then add the rest of the butter) fry the tuna steaks over moderate heat until they are lightly browned on the outside but still pink at heart. When they are done I remove them to the plate and put the onions and lardons back in the pan to heat. Add vinegar and season to taste with salt and pepper. I then heat serving plates and place a puddle of the onion and lardons on it and place a tuna steak on top.

YUM!