In a small bowl, whisk
together the vinegar, oil, Worcestershire, thyme, parsley, garlic, lemon juice
, and salt and pepper. Put the flank steak in a wide shallow dish and coat with the marinade. Refrigerate for 45 minutes to 1 hour.
Preheat a grill on high.
Remove the outer skin (rind) of the brie and dice
it into 1/2-inch cubes. Add them to a small bowl and toss them with the cornstarch. In a medium saucepan
over high heat, add the wine and bring to a boil. Add the brie and stir until the cheese
has melted. Once melted, reduce the heat to medium-low and stir in the thyme
, salt and pepper, to taste. Cook for 5 to 6 minutes. Remove the fondue from the heat and transfer it to a fondue pot
to keep warm.
Remove the steak from the marinade
, straining the excess marinade and put it in the middle of the preheated grill. Cook until desired temperature is reached, about 9 to 10 minutes per side. Remove from the grill
to a cutting board and let rest for 5 to 10 minutes.
Slice it on the bias and arrange them on a serving platter. Drizzle
with fondue sauce or serve it on the side in a fondue pot.