• Prep Time: 2 hours 15 minutes • Yields: 2 servings
1 sheet of puff pastry
8 oz. brown mushrooms, rinsed and dried
1 tsp. + 2 tbsp. olive oil
¼ tsp. kosher salt
⅛ tsp. black pepper
1 tbsp. Dijon mustard
3 oz. prosciutto, 6 to 8 slices
½ cup water, as needed to brush the pastry
1 large egg yolk
1 tbsp. milk
1. Defrost puff pastry by placing on a sheet pan lined with parchment paper and tightly covering with plastic wrap until pliable yet cool, about 30 - 40 minutes.
2. Place rack in the middle of oven and preheat to 400°F.
3. Pulse mushrooms in a food processor until texture is similar to breadcrumbs or chop as finely as possible with a chef’s knife. Then, heat olive oil over medium heat in a medium- sized pan. Sauté mushrooms until mixture is soft, about 5 minutes. Transfer mushrooms to a small bowl and season with salt and pepper. Refrigerate until cooled.
4. Form filets into rounds by tying them with butcher’s twine to hold the shape as they cook in pan. Then, pat steaks dry and season each side generously with salt and pepper.
5. Heat remaining olive oil in a large skillet over medium-high heat. Add filets to pan, press down, and brown for 2 minutes on each side. Sear raw edges of meat to brown them. Remove filets from pan and let cool. Note: save meat drippings for use later in recipe.
6. Cut off butcher’s twine, brush Dijon mustard all over each filet, and set aside.
7. Place a large piece of plastic wrap on cutting board. Lay 3 - 4 slices of prosciutto down, enough to completely cover filets, slightly overlapping each piece about ¼”. Spread half of mushroom filling over prosciutto, leaving about a ½” border along the sides. Then, place filet in center of prosciutto. Use the plastic wrap to draw the prosciutto around fillet, covering all sides. Roll up and twist ends of film to tighten and refrigerate for 5 minutes.
8. Roll pastry sheet into an 11” x 11” square. Lightly dust the surface with flour if it sticks to the rolling pin. Cut pastry sheet in half, making two 5 ½” x 11” rectangles.
9. Place prosciutto-wrapped bison fillets in the center of each pastry sheet. Lightly brush edges of pastry with water. Bring opposite corners of the longer sides of pastry over and press seams to seal tightly. Fold the shorter sides up to enclose the other portions. Wrap with plastic wrap and refrigerate for 5 minutes to allow pastry to firm up again.
10. Whisk egg yolk and milk in a small bowl. Place wellingtons, seam side down, on a sheet tray lined with parchment paper, and brush with egg wash. Bake until pastry is golden brown, and internal temperature reaches 125°F for medium-rare or 130°F to 135ºF for medium, about 20 to 30 minutes. Pull from the oven and rest for at least 10 minutes before slicing and serving.