Mix wine, garlic, oil, rosemary, thyme and allspice in a large resealable plastic bag. Add pork and turn to coat. Marinate for 1 hour, turning occasionally.
Preheat oven to 375 degrees. Remove pork from marinade and place on a rack on a rimmed baking sheet; discard marinade. Spread 3 tbsp. Dijon over pork. Roast until thermometer inserted into thickest part of pork reaches 145 degrees (about 25-35 minutes.) Transfer pork to platter, cover with foil and let rest for 10 minutes.
Meanwhile bring cream, broth, tarragon and remaining 2 tbsp. Dijon in heavy sauce pan to a boil and then simmer until reduced to 1 cup, whisking occasionally, about 10 minutes. Season to taste with kosher salt and pepper. Slice pork and serve with sauce.