Instructions

1. DAY 1
2. Make a rub. In a food processor, blend 2 tsp (10 ml) salt, 1 tsp (5 ml) pepper, 6 sprigs thyme leaves, sage and garlic until herbs are finely chopped. Set aside.
3. In a small saucepan, melt 2 tbsp (30 ml) butter. Set aside.
4. Remove tenders from breast and keep for another use. Using a sharp knife, butterfly thick side of 1 breast and fold cut piece outwards so it lies flat. Repeat on other side.
5. Score entire breast halfway through thickness of meat, making cuts 1-in (2.5 cm) apart. Repeat with second set of cuts perpendicular to first.
6. On counter, lay out a piece of foil double the size of breast. Sprinkle rub evenly over breast and rub into meat. Drizzle melted butter evenly overtop.
7. Carefully roll meat into a tight cylinder. Place cylinder on foil and wrap it up, then wrap tightly in plastic wrap. Place in refrigerator overnight, up to 24 hours.
8. DAY 2
9. The next day, remove turkey from refrigerator and let sit at room temperature for 1 hour. Preheat oven to 350 F (175 C). Remove plastic wrap from turkey (leave foil on), place on a baking sheet and bake until internal temperature reaches 165 F (74 C), about 1½ to 2 hours. Remove from oven and cool to room temperature, then transfer to refrigerator and chill completely, preferably overnight.
10. In a food processor, finely chop hydrated mushrooms and button mushrooms.
11. In a large saucepan over medium heat, melt remaining 2 tbsp (30 ml) butter with olive oil. Sweat leeks until soft. Add chopped mushrooms and remaining 1 tsp (5 ml) salt, 1 tsp (5 ml) pepper and 2 sprigs thyme leaves. Cook until mushrooms have released all their juices. Add liquid from hydrating mushrooms, avoiding any grit. Continue cooking, stirring occasionally, until all liquid has evaporated and mushrooms have slightly browned. Transfer to a container and cool, then place in refrigerator until cold.
12. DAY 3
13. Remove foil from turkey, dry with paper towel and set aside at room temperature.
14. In a medium bowl, mix mushrooms with eggs and bread crumbs and set aside.
15. In a separate bowl, mix egg yolks with cream and set aside. This is your egg wash.
16. Dust counter with flour and lay out 1 package of puff pastry, dusting with more flour and rolling it out if necessary so it is large enough to roll turkey in. Brush with egg wash.
17. Lay prosciutto on half the pastry. Spread mushrooms over prosciutto. Place turkey on 1 side of pastry and roll it up in pastry. Tuck pastry underneath and place on a parchment-lined baking sheet. Place in refrigerator.
18. Dust counter with flour and lay out second package of pastry. Dust pastry with flour. Make 1-in (2.5 cm) vertical cuts across pastry, then repeat until you have made cuts on entire sheet. Alternatively, use a lattice pastry cutter. Brush off excess flour. Brush Wellington with egg wash. Place cut pastry on top of Wellington, then place in refrigerator until ready to cook.
19. Preheat oven to 400 F (200 C).
20. Remove Wellington from refrigerator and brush with egg wash.
21. Bake Wellington for 15 minutes, then turn heat down to 350 F (175 C) and bake for another 45 to 55 minutes, or until pastry is golden brown and cooked through, rotating halfway through baking.
22. Remove from oven. Serve with cranberry sauce and your favourite turkey gravy.