Preheat oven to 400*
Get out and measure all of your ingredients.
Heat a cast iron skillet over medium high heat.
Add garlic powder, onion powder, sea salt, and black pepper to a ramekin
Stir to until blended.
Season all sides of the tenderloin with seasoning.
Rub until covered.
Add 1 tbsp olive oil to the skillet and swirl to coat. Sear each side of the tenderloin for 2 minutes per side. Cut the head of garlic in half and add to the pan cut side down. Add butter to the pan and cook for 1 minute, spooning butter over the steak as it cooks.
Place the garlic halves into the center of the skillet and sit the steak on top of them. Place into the oven and cook for 12 minutes. (12 minutes for medium rare, 15 minutes for medium)