1. Preheat oven to 300F.
2. Pat tenderloin dry. Combine salt, black pepper, garlic cloves, rosemary, and olive oil in a bowl. Evenly spread mixture on all sides of the tenderloin.
3. Heat butter in a large cast iron skillet over high heat. Add tenderloin and cook until all sides are well browned, about 10 minutes.
4. Transfer skillet to the oven and cook for 15 minutes, or until the internal temperature is 130F.
5. Let meat rest for 15 minutes. While resting, heat Main St Bistro® Steakhouse Yukon Gold Mashed Potatoes via package instructions.
6. Slice meat and serve.
Created by Tasting With Tina
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