- 1 kg / 2 lb beef tenderloin
- Olive oil
- 1 spring of fresh thyme
- 2 tbsp mustard
- 500g-700g chestnut mushroom, can mix with other mushrooms of your choice
- 8-12 slices prosciutto
- 50 g butter
- 500g / 1lb 2oz pack puff pastry, thawed if frozen
- flour, for dusting
- 1 egg yolk beaten with 1/2 tsp water
- Season the tenderloin with salt and pepper.
- Brown the beef in a skillet with olive oil at high heat, on all sides, and then set aside on a plate. Brush the tenderloin with mustard.
- Chop the mushrooms finely using a knife or food processor to a texture of coarse breadcrumbs.
- Add butter to a skillet on medium heat and fry the mushroom with the thyme until all liquid has evaporated. Season with salt and pepper
- Lay cling film on a counter (overlap two pieces if needed) and then lay the prosciutto on the cling film overlapping somewhat in a double row.
- Spread half the duxelles (mushroom mixture) over the prosciutto and pat it down with a spoon.
- Place the tenderloin on the duxelles furthest to the side where you plan to start rolling.
- Hold the cling film and roll until the prosciutto is wrapped all around the beef. Twist the end of the cling film to make it as tight as possible and let it rest in the fridge.
- If using frozen (now tawed) puff pastry, lay the puff pastry on a cling film, dust with a little bit of flour, and carefully roll together the edges into one piece of puff pastry. If using one piece puff pastry, put it on a piece of cling film (overlapping if needed). For tawed puff pastry, if possible move it to a piece of cling film or role it in the parchment paper and then move it to a piece of cling film.
- Unravel the Proscuitto wrapped tenderloin from the cling film and place it in the center of the puff pastry. Holding the edge of the cling film, roll the tenderloin. Close the puff pastry edges, on all three sides (cut off any access puff pastry as needed). Twist the end of the cling film to make it as tight as possible.
- Let it chill for at least 30 minutes or overnight if you plan to bake the next day.
- Beat the egg yolk and water and brush the puff pastry.
- Create a pattern on the dough if you prefer and sprinkle flaky salt on top.
- Bake in the oven at 200°C / 392°F for 30 minutes for medium-rare.
- Serve with red wine sauce.