In a small bowl, stir together garlic, mustard, vinegar, oil, espresso powder, salt, and pepper. Place steak into a large, shallow dish, and rub garlic mixture on all sides of beef. Top with shallot and parsley. Cover and refrigerate 8 hours or overnight.
Spray grill rack with nonstick nonflammable cooking spray, and preheat grill to high heat (400 to 450°). Grill meat 3 minutes per side for medium-rare or until desired doneness. Remove from heat, and let stand for 5 minutes before slicing.