grilled cheese steak sandwich

Ingredients:

• 1/4 cup olive oil
• 1 tablespoon white balsamic vinegar
• 3/4 teaspoons dry mustard, divided
• 1 tablespoon dark brown sugar
• 2 pounds well-trimmed tri-tip beef roast
• 1/2 cup shredded white Cheddar cheese
• 6 French baguettes, cut horizontally almost in half, opened flat

Prepare barbecue on medium-high heat. Whisk oil, vinegar, sugar, and mustard in bowl. Season with salt and pepper.  Sprinkle beef all over with salt and pepper, then top with mixture. Grill beef until thermometer inserted into thickest part registers 120F to 125F degrees. Cook until desired doneness is achieved. Place on cutting board and let rest 10 minutes. Cut very thinly across grain.  Grill bread, cut side down, until just crusty. Place on plates and arrange beef slices over bread. Sprinkle with cheese and top baguette and serve.