Combine cheese, butter, parsley and 1/2 teaspoon rosemary in medium bowl. Stir to blend well. Season to taste with salt and pepper. Transfer blue cheese butter to small bowl. (Blue cheese butter can be prepared 2 days ahead. Cover and refrigerate. Bring butter to room temperature before using.)
Combine 1/2 tablespoon rosemary, garlic, salt and pepper in processor. Blend until mixture resembles coarse paste. Pat steaks dry. Place in large baking dish. Rub 2 teaspoons of garlic paste on each side of each steak. Cover and let stand 1 hour at room temperature.
Pre-heat grill (medium-high heat).
Grill steaks to desired doneness, about 5 minutes per side for medium-rare.
Transfer steaks to platter and let stand 5 minutes.
Cut each steak into 2 equal portions. Top each portion with a spoonful of blue cheese butter and serve.