Step 1

Make the marinade. Place the olive oil, balsamic vinegar, mustard, garlic, and salt in gallon zip-top bag. Seal and shake to combine.

Step 2

Marinate the steak for 1 hour or overnight. Add the steak to the marinade and seal the bag. Place the bag in a baking dish or rimmed baking sheet. Refrigerate at least 1 hour or overnight.

Step 3

Prepare the steak for grilling. Remove the steak from the marinade and pat dry. Discard the marinade.

Step 4

Grill the steak over high and medium heat. Heat half of an outdoor grill for high, direct heat. Heat the other half for medium, direct heat. Place the steak over high heat until browned, burnished, and grill marks appear, about 2 minutes per side. Move the steak to medium heat and continue grilling to desired doneness, 3 to 5 minutes more for medium (about 140°F).