Combine mint, parsley, oil, broth, vinegar, shallots, red pepper, garlic, 1/4 teaspoon salt, and 1/4 teaspoon black pepper in a food processor; process until blended.
Sprinkle lamb loin chops on both sides with remaining 1/2 teaspoon salt and remaining 1/4 teaspoon black pepper.
Heat a grill pan over medium-high heat. Coat pan with cooking spray.
Add lamb to pan; cook for 5 minutes on each side or until desired degree of doneness.