Mix sugar, salt, and herbs in dry stainless steel bowl. Rub pork loin with olive oil and garlic, then massage the brown sugar and herb mixture into the meat. Let the pork loin marinate overnight in the refrigerator.
Preheat the oven to 300 degrees F.
Remove pork from the refrigerator and coat it with the excess marinade in the bottom of the pan. Transfer to the oven and cook until the internal temperature measures 145 degrees F on a meat thermometer. Remove from heat and let rest, tented with foil, for 20 minutes; the internal temperature should rise to about 150 degrees F.
While pork is roasting, make Mushroom Ragout Sauce.
When ready to serve, slice pork as desired. For each serving, spoon 1/2 cup mashed potatoes in center of plate and sprinkle with candied pecans. Arrange pork on top of mashed potatoes and spoon 1/2 cup Mushroom Ragout onto each plate. Garnish with blue cheese crumbles and fresh mint and serve.
Mushroom Ragout Sauce:
2 tablespoons diced pancetta
1 tablespoon olive oil
1/4 cup julienned yellow onions
1/2 tablespoon chopped shallots
1 teaspoon minced garlic
1 teaspoon lemon zest
1/4-pound portobello mushrooms, chopped
1/4-pound oyster mushrooms, torn by hand
1/2 teaspoon Worcestershire sauce
1 cup chicken demi-glace
1/2 teaspoon chopped fresh rosemary leaves
1 tablespoon diced Roma tomatoes
1 tablespoon whole butter
Render the pancetta in a braiser over medium heat until crisp. Add the olive oil, onions, and shallots. Cook until onions are starting to caramelize, and then add garlic and lemon zest and cook for a moment to release aromas. Add in mushrooms and saute until they break down, release their moisture, and liquid evaporates. Add Worcestershire and demi-glace. Stir in rosemary, tomatoes, and butter until incorporated.