In a small bowl combine garlic, mustard, honey, balsamic vinegar and beer. Stir in ginger. Place steak in baking pan and pour marinade over and toss to coat. Cover with plastic wrap and refrigerate overnight. Remove from pan and season with salt and pepper. Grill on barbecue or cast iron pan for 3 - 5 minutes per side depending on desired degree of doneness. Slice thinly and serve.