Ingredients:

1 ½ pounds ground sirloin
1 shallot, finely chopped
2 to 3 tablespoons finely chopped fresh parsley,
1 tablespoon Worcestershire sauce (eyeball it)
Salt and freshly ground pepper
Extra-virgin olive oil (EVOO), for drizzling
3 tablespoons butter
½ pound cremini or white mushrooms, sliced
¼ cup dry sherry
2 tablespoons Dijon mustard
4 eggy rolls, split and toasted, or 8 thick slices challah bread,toasted
1 small bunch watercress,chopped
½ cup chopped cornichons or baby gherkin pickles
½ pound truffle mousse pate.

Directions:

In a medium bowl,mix together the meat, shallot, parsley and Worcestershire sauce;season with salt and pepper.Score the meat into 4 equal portions and then form into large patties using BurgerMate.Heat a drizzle of EVOO in a large nonstick skillet over medium-high heat.When the pan is screaming hot,add the patties and cook for 4 minutes on each side for medium rare, 6 minutes on each side for medium well.

Meanwhile,place a medium skillet over medium heat. Melt 2 tablespoons butter in a drizzle of EVOO,add the mushrooms and cook until tender,about 6 minutes.Pour in the sherry and let cook off,about 30 seconds.Season the mushrooms with salt and pepper and remove from the heat. Stir together the mustard and remaining 1 tablespoon butter.Spread the Dijon butter liberally on the bun bottomsTop with the watercress, a burger patty,a pile of mushrooms and a few chopped cornichons.Spread the mousse pate on the bun tops and set them into place.