Season both sides of the steak with salt and pepper. Tie steaks using cooking twine around the sides to form into medallions.
Allow steaks to come to room temperature and the salt to melt into the meat (30 to 45 minutes). Season lightly with cayenne pepper.
Preheat a cast iron skillet over medium high heat. Preheat the oven to 250 degrees F. Preheat a second skillet over medium heat.
Cook the Medallions
Once the cast iron skillet is hot, add the olive oil and sear the medallions in there for 3 minutes. Flip the steaks, add the butter and crushed garlic and sear for 3 more minutes, spooning butter over the steaks as they sear.
Remove from heat and place crushed garlic on top of each.
Place into the oven and cook for 8 to 11 minutes (8 to 10 minutes for medium rare, 10 to 11 minutes for medium) or until done to your liking.
Prepare the Tomato Relish
While the steak is cooking, prepare tomato relish. Add chopped red onion, peppers, and cherry tomatoes to a food processor.
Pulse 2 to 3 times to lightly break up the vegetables.
Add to a saucepan with white wine vinegar and cook for 5 minutes over medium low heat. Remove from heat and add to a small bowl. Stir in chopped basil and set aside.
Prepare the Horseradish Cream
Add horseradish, sour cream, and minced garlic to a small bowl and whisk to combine.
Plate and Serve
Plate the steak over the tomato relish and top with horseradish cream.
Notes
Rest the steaks: Always let meat rest before slicing to keep the juices inside. Spoon butter constantly: While searing, this helps create a deeply flavorful crust. Check internal temperature: Use a meat thermometer for the perfect doneness every time.