Heat a grill plate over a woodfired barbecue to low-medium heat, add onions and turn occasionally until tender (1-1½ hours). Keep warm.
Stoke the fire to medium heat, add T-bones, season to taste and cook, turning once, until cooked to your liking (8-10 minutes each side for medium). Set aside in a warm place to rest (5-10 minutes). Season to taste with sea salt flakes just before serving.
Meanwhile, warm oil, herbs and peppercorns gently in a small saucepan on the side of the barbecue.
Remove any burnt skin from onions, then cut a cross in the top of each, dot with Taleggio and season generously. Serve with T-bones drizzled with herb oil, with lemon wedges for squeezing.
This recipe is from the January 2012 issue of Australian Gourmet Traveller.