2 (7-8 ounce) beef filets, patted dry, season with salt and pepper
8 slices prosciutto
sautéed mushroom mix (recipe below), chilled
2 sheets puff pastry, thawed according to package instructions
1 egg yolk, whisked with a fork
Lay a large piece of plastic wrap down on the counter. Lay 4 slices of prosciutto down slightly overlapping. Spread a layer of the mushroom mixture down on the prosciutto. Place a beef filet down in the middle. Fold the plastic wrap up and around the filet, twist the ends until tight to seal. Place in the refrigerator to chill for 30 minutes.
Lay a new sheet of plastic down and top with a sheet of puff pastry. Remove the chilled filet, remove it from the plastic and carefully wrap the filet in the dough, trimming any excess needed. Fold the plastic wrap up around the filet, twisting the ends as before. Chill for at least 30 minutes.
To cook, preheat your oven to 425°F. Line a baking sheet with parchment paper. Remove the filet form the refrigerator and remove the plastic as before. Transfer the filet to the baking sheet. Brush with the egg yolk and sprinkle with sea salt. Bake for about 16-18 minutes for medium rare.
Sautéed mushroom mix
2 pounds mixed mushrooms, divided in half
1 tablespoon butter
1 small shallot, minced
2 garlic cloves, minced
1 teaspoon chopped tarragon
¼ teaspoon finely chopped thyme
¼ teaspoon finely chopped rosemary
salt and pepper, to taste
Chop half of the mushrooms and transfer to a food processor. Pulse until finely ground. Cook in a dry sauté pan over low heat until the moisture is released. Set aside.
Thinly slice the remaining mushrooms, and sauté in a drizzle of oil and the butter until the moisture is released. Add the herbs, season with salt and pepper to taste.
Combine both mushrooms and place in the refrigerator to chill.