Preheat the oven to 425 degrees F. Prepare the pork: Whisk the thyme, rosemary, garlic, mustard and vegetable oil until emulsified. Season with salt and pepper.

Rub the pork liberally with the herb-mustard mixture, then place fat-side up on a rack set inside a heavy-bottomed roasting pan. Roast until the pork is caramelized and a thermometer inserted into the center registers 145 degrees F, 55 to 60 minutes. Transfer to a cutting board and let rest 10 minutes.

Meanwhile, make the sauce: Pour off all but 2 tablespoons drippings from the roasting pan, then heat on the stove over medium heat. Add the mushrooms and cook until caramelized, 6 to 8 minutes. Add the shallots and cook until translucent, about 2 more minutes. Remove the pan from the heat and add the cognac, then return to the heat and scrape up any browned bits from the bottom of the pan with a wooden spoon. Simmer until almost all of the liquid has evaporated. Whisk in the stock, mustard and thyme. Bring to a boil and cook until reduced by half, 8 to 10 minutes. Add the cream and butter and gently boil until thickened. Add the parsley and salt and pepper to taste.

Slice the pork into 12 pieces and drizzle with the sauce.

*Serve with German Potato Salad and Braised Red Cabbage.