Dice the beef into very small pieces, flatten them on a plate and place in the refrigerator for 30 minutes (the beef should become brighter red as it sits).
After the beef has chilled, combine it in a bowl with the shallots, garlic, capers, 1 teaspoon of the parsley, Worcestershire sauce, Dijon mustard, egg yolk, the truffle oil and 1 tablespoon of the Parmesan. Mix well and salt to taste, then pack the tartare tightly into a ring mold and place on plate and chill until ready to serve.
Cut the bread into quarter-inch-thick slices, lightly rub with the olive oil and season with salt. Grill the slices on both sides, then sprinkle the remaining parsley on top.
Unmold the tartare, garnish with the remaining Parmesan and serve with the grilled bread.