- Sauté mushrooms at medium heat in a non-stick pan until completely cooked.
- Add the diced shallots, chopped garlic and fresh thyme and sauté for a couple of minutes.
- Deglaze with the Sherry and reduce until dry.
- Add the Sherry vinegar, truffle oil, salt and pepper, and remove the mixture from the pan into a container. Place into refrigerator to cool down.
- Spread the cooled down mushroom mixture evenly on one sheet of puff pastry, leaving 1” (2.5 cm) gap on all sides.
- Using a pastry brush, brush the plain part of the pastry dough with the egg wash to create a seal.
- Place the turkey breast in the centre of the sheet and cover with the remaining sheet of puff pastry, making sure the dough completely covers the turkey breast.
- Press the sides down with a fork to ensure the breast is completely sealed inside. Place on parchment paper, on a baking pan. Brush with egg wash to completely cover the dough, sprinkle with coarse salt.
- Let sit in the refrigerator for ½ hour.
- Bake in a pre-heated oven at 400oF (205oC) for 30 minutes, then turn the oven down to 320oF (160oC).
- Using a meat thermometer, bake until the internal temperature reaches 170oF (76oC) (probe in the largest part of the breast through the dough).
Once cooked, let sit for 15 minutes before using a bread knife to slice into portions and serve immediately.