Cut the pork tenderloin into 8 rounds, about 1" thick. Using a meat mallet, pound pork pieces until ¼″ thick. In a large bowl, toss the pork with 1 tablespoon olive oil, oregano, dijon mustard, and pepper. Marinate 15 minutes.
Heat the remaining 1 tablespoon olive oil in a 10-inch skillet over medium-high heat. Cook pork for 2 minutes on each side, or until cooked to 145℉, cooking in batches if needed. Set pork aside on a plate and cover.
Combine the cream, chicken broth, Dijon, horseradish, tarragon, and garlic powder in the skillet. Bring to a boil, reduce heat, and simmer until thickened (about 10-12 minutes). Remove from heat and whisk in butter.
Add pork medallions to the sauce and serve.
Notes
Pound pork medallions between parchment for quick clean up.
Be sure to give the sauce ample time to thicken in the skillet.
Refrigerate leftovers in a covered container for 3-4 days. Freeze in a sealed zippered bag for 3 months.
Thaw pork in the refrigerator, then reheat on the stovetop or covered with foil in the oven.
To grill: Preheat grill to high. Grill the Pork Medallions on high 3-4 minutes per side or until just slightly pink inside. Remove from heat, let rest a few minutes.