Easy enough for any night, and special enough for company!
For the oven: Preheat oven to 425F. Sear the medallions on both sides on the stove-top in a non-stick pan over medium-high heat. Transfer to an oven-safe skillet or pan and roast in the oven for 15 minutes, turning the medallion over once about halfway through cooking, or until 140F internal temperature.
If you'd like to serve with potatoes, as shown in the recipe photos, simply dice up some potatoes and onion and toss with olive oil and season with salt and pepper. Roast in preheated oven for 30 minutes, stirring often, until tender and lightly golden.