Heat your cooker (I used my Cadac Portable Grill with a grill-late attachment), the grill should be sizzling hot.

Place the onion rings in a Dutch Oven and arrange the thyme sprigs around the side. Pour the wine over the top, then cover with the lid and place over low hear (an area of the grill without many coals; use tongs to move a few coals in necessary). Simmer gently for 20-30 minutes or until the onion is softened translucent and the red wine has reduced to a runny sauce.

Add the steak to the hot part of the grill, sprinkle with salt and cook until the meat is medium-rare depending on the thickness of the steaks, this should take about 5 minutes with an internal temperature of 130°F (54°C). Allow the steaks to rest, covered, for 5 to 10 minutes before slicing the internal temperature will increase a little to yield a perfectly cooked medium-rare steak.

Slice the steaks and serve with the onions and red wine sauce.