Slice elk tenderloin into thick slices, about 10 slices per tenderloin.
Heat cast iron skillet over medium heat, add 3 Tablespoons butter and fry the medallions in the butter for 1-2 minutes per side or until a meat thermometer reaches 145℉.
Remove the meat from the skillet, place on a warm plate and cover.
Add the remaining 3 Tablespoons butter to the skillet and sauté for 5-7 minutes or until soft. Mince the garlic and add for the last 30 seconds.
Remove mushrooms and garlic, adding them to the warm plate with the meat.
Add cream to the same skillet, also add the thyme, salt, pepper, balsamic vinegar and wine. Stir and cook for a minute or two till warm and bubbly. Scrape the bottom of the skillet to include all of the flavor from the browned bits.
When sauce is warm and seasoned to taste, add the meat, meat juices, and mushrooms back in and remove skillet from heat. Serve immediately.
Notes
This recipe works great for elk, moose, or deer. If you are using both tenderloins, just double the sauce. Use whatever cooking wine you have on hand. I had some red wine in my fridge so that is what I used. You can also replace the wine with beef broth if desired.