Grilled Flank Steak Sandwiches

Ingredients (18)

• 1.5 lbs. flank steak
• 1/4 cup olive oil
• 3 cloves garlic
• 2 Tablespoons red wine vinegar
• 1/3 cup soy sauce
• 2 Tablespoons honey
• 1/2 teaspoon ground pepper
• 1 Tablespoons butter
• 2 Tablespoons olive oil, divided
• 1 large yellow onion, thinly sliced
• 8 ounces sliced mushrooms
• Pinch salt
• 1 large french baguette, cut into fourths (or two smaller ones cut in half)
• 8 slices white cheddar cheese
• 1/4 cup mayo
• 1/4 sour cream
• 2 Tablespoons creamed horseradish spread
• Sliced Tomato