Thoroughly combine softened butter with garlic vinegar, cayenne, salt, and pepper. Roll with plastic wrap into a log shape, 1 inch in diameter. Refrigerate 2 hours or until compound butter is solid. Make 1 day ahead, if possible.
Preheat Bravo and set to broil for 500°F.
Remove steaks from refrigerator and bring up to room temperature, about 20 minutes. Pat dry and season with salt and pepper.
Spray enamel baking pan with cooking spray. Place steaks in baking pan. Insert Probe thickest part of steak. Set Probe to 120°F for medium-rare.
When done, remove steaks and let rest 5 min. Place slab of garlic butter on meat and let melt to infuse flavor. Serve immediately.