In a small bowl, whisk together the mustard, Worcestershire sauce, Tabasco, ketchup, and brandy, if using. In another bowl, combine the shallots, garlic, capers, herbs, and hazelnuts, if using. This can be prepared up to an hour ahead.
At the very last minute, chop the meat into 1/4 inch dice (not too fine) using a large sharp knife. In a medium mixing bowl, combine the meat, egg yolks, and mustard mixture with a fork. Season with salt and pepper. Fold in the shallot mixture and blend well.
Divide the meat in four equal portions and arrange them in patties on serving plates (use cylindrical moulds if you have them). Serve immediately, with additional mustard, Worcestershire sauce, Tabasco, ketchup, salt, and pepper on the table for each guest to adjust the seasoning.