For brining: In a bowl, mix 12 cups of water, 4 Tbsp of salt, 4 Tbsp of sugar, ½ cup of vinegar, 2 bay leaves and 1 Tbsp of ground pepper. Add turkey breast in the prepared brine and keep in the refrigerator for 12 to 24 hours.
For the stuffing
- Preheat oven, rack in the middle, at 375°F (190°F).
- In a hot pan, brown onion in olive oil, 5 minutes.
- Add mushrooms, garlic, cranberries and continue cooking, 5 minutes.
- Add beer, maple syrup and reduce until dry at medium heat, approx. 5 to 10 minutes,
- Finely chop stuffing.
- Butterfly turkey breast and, if necessary, cut other pieces, to create an even thickness.
- Season all sides of the turkey breast with salt and pepper.
- Stuff turkey breast with prepared stuffing, roll and firmly tight breast from one end to the other with kitchen twine.
- Transfer roast in a roasting pan and cook in the oven for 1 hour and 30 minutes, or until internal temperature reaches 165 °F (74 °C).
- In a pan, melt butter and brown shallot, 3 minutes.
- Add thyme, garlic and veal stock and let reduce to a syrupy consistency.
- Add cream, mix, adjust seasoning and pour on roast.