Lobster-Stuffed Beef Tenderloin with Bearnaise sauce

Preheat oven to 400 F.

In a large skillet, heat 1 teaspoon of oil over medium-high heat. Add Pancetta and cook, stirring, until crisp and the fat is rendered, about 5 minutes. Remove with slotted spoon. Drain off all but 2 teaspoons of fat from the pan. Add the shallots and celery and cook ,stirring, until soft, about 2 minutes. Add the garlic and cook stirring,for 30 seconds. Add the mushrooms and a pinch each of salt and pepper, cook until the mushrooms give off their liquid, 3 to 4 minutes. Add the green onions and stir. Add the wine, increase the heat, and cook until it has nearly evaporated, 1 to 2 minutes. Add the parsley and stir. Remove from the heat, stir in the cooked pancetta, and let cool.

Spread butterflied beef, cut sid up, flat on surface. Spread the pancetta-vegetable mixture in a line across the meat, about 2 inches from the top, leaving a 1/2 inch border on the sides. Lay lobster on top of the mixture, going across the beef. Pull the top flap over the lobster and roll the meat over the stuffing, jellyroll fashion, and tuck the ends.Tie with kitchen twine every 2 inches.

Place in a large heavy roasting pan, rub on all sides with remaining- 2 teaspoons olive oil, and season with salt and pepper. Place over medium-high heat and sear meat on all sides, about 6 minutes. Place in oven and roast to desired temperature, 30-35 minutes for medium rare.

Transfer to cutting board . Tent and rest for 10 minutes before carving. Remove kitchen twine and slice thickly. Place on platter, surround by asparagus, and drizzle with Bearnaise sauce.

Bearnaise Sauce:

2 tablespoons shallots

4 sprigs tarragon

1/4 cup dry white wine

1/4 cup vermouth

4 large egg yolks

1 cup melted unsalted butter

1 teaspoon lemon juice

2 tablespoons tarragon leaves

1/2 teaspoon salt

1/8 teaspoon white pepper

In a small saucepan, combine the shallots, tarragon, white wine, and vermouth. Bring to boil and cook till reduced to 2 tablespoons. Remove from heat, strain and cool.

In the top of a double boiler, or metal bowl fitted over top of pot of barely simmering water, whisk the egg yolks and reduce wine until ribbons start to form. Whisking constantly, drizzle in the melted butter a bit at a time until all the butter is added and mixture is thick. Remove from heat. Whisk in lemon juice, chopped tarragon, salt and pepper. Adjust the seasoning, to taste. Cover to keep warm until ready to serve, To serve, place in a decorative bowl with a small sauce ladle