# Components:
→ Beef
01 - 6 beef filet medallions, 2–3 oz each, about 1½ inches thick
02 - Kosher salt, to taste
03 - Freshly ground black pepper, to taste
→ Mushroom Duxelles
04 - 8 oz cremini or button mushrooms, finely chopped
05 - 1 small shallot, finely minced
06 - 2 cloves garlic, minced
07 - 2 tablespoons unsalted butter
08 - 1 tablespoon fresh thyme leaves, chopped
09 - Salt, to taste
10 - Freshly ground black pepper, to taste
→ Assembly
11 - 1 sheet all-butter puff pastry (about 14 oz), thawed if frozen
12 - 3 oz prosciutto, thinly sliced
13 - 1 large egg, beaten (for egg wash)
14 - All-purpose flour, for dusting
# Method:
01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper and set aside.
02 - Pat the beef medallions dry and season both sides liberally with kosher salt and freshly ground black pepper.
03 - Heat a skillet over high heat until smoking, add a light film of oil, and sear the medallions 1 minute per side to develop color while keeping the center rare. Transfer to a plate and allow to cool completely.
04 - Using the same skillet, reduce heat to medium and melt the butter. Add the minced shallot and garlic and sauté for about 1 minute. Add the chopped mushrooms and thyme, season with salt and pepper, and cook, stirring frequently, until all moisture evaporates and the mixture is dry, about 8 minutes. Remove from heat and cool completely.
05 - On a lightly floured surface, roll the puff pastry to approximately 1/8 inch thickness. Cut the sheet into six squares large enough to fully enclose each medallion.
06 - Place a slice of prosciutto in the center of each pastry square, spread a spoonful of the cooled mushroom duxelles over the prosciutto, then set a cooled beef medallion on top.
07 - Lift the pastry edges up and around the medallion, trimming any excess dough and ensuring a secure seal. Place each parcel seam-side down on the prepared baking sheet.
08 - Brush each parcel all over with beaten egg. If desired, use trimmed pastry to create decorative shapes and adhere them with egg wash; brush decorations as well.
09 - Bake in the preheated oven for 18–20 minutes, or until the pastry is deep golden and crisp. Remove from the oven and let rest 5 minutes before serving.
