Slice the pork tenderloin into 1 ¼ to 1 ½ inch thick medallions, about 10-12 pieces. Place the sliced meat in a ziplock bag or large bowl.

Whisk together the balsamic marinade ingredients and add the marinade to the pork tenderloin medallions, coating them evenly.

Marinate for 30 minutes to 1 hour in the fridge. (See notes for marinating longer)

Once marinated, remove the pork from the fridge and let it come to room temperature, about 15-20 minutes.

Heat a large skillet over medium heat. Add 2 teaspoons of olive oil. When the oil is hot and starts to sizzle, add the marinated medallions to the skillet (reserve leftover marinade) and let them cook for 3 minutes on the first side. Flip and cook an additional 3-4 minutes until they are golden brown then remove the medallions from the pan.

Add the onion to the pan (there should be juices left from the pork) and sauté onion about 2 minutes or until slightly brown, scraping up the browned bits on the bottom of the pan.

Add the remaining marinade sauce to the pan. Let it come to a high simmer for 1 minute, bubbling up, then return the medallions and baste them in the sauce. Let them simmer in the sauce for an additional 1 minute or the internal temperature reaches 145 F.

Remove the pork from the skillet, letting it rest for 3 minutes after cooking to redistribute the juices.

Plate the pork medallions and top with the reduced marinade, onion, and fresh chopped herbs. If desired, season with salt and black pepper.

Store leftovers in an airtight container for up to 3 days in the fridge.