Ingredients

• For the marinade:
• 2 Tablespoons olive oil
• ¼ cup balsamic vinegar
• 3 Tablespoons low-sodium soy sauce
• 1 Tablespoon Dijon mustard
• 1 Tablespoon honey
• 3 garlic cloves, finely chopped
• For the horseradish mayo:
• ¾ cup mayonnaise
• 1 ½ Tablespoons bottled horseradish
• 1 teaspoon lemon juice
• ¼ teaspoon ground paprika
• Remaining ingredients:
• 1 lb flank steak, thinly sliced against the grain
• 2 Tablespoons olive oil, divided
• 1 red onion, sliced
• 2 large tomatoes, sliced
• 1 avocado, sliced
• French baguette, cut into 6 inch pieces, and sliced horizontally

Instructions

1. Combine the marinade ingredients, using a whisk or a fork, making sure everything is well incorporated. Place the sliced steak pieces in the marinade, cover and refrigerate for 1 to 2 hours.
2. Pre-heat the oven to 400 degrees.
3. Combine the horseradish mayo ingredients, and refrigerate.
4. Place tomato slices in a baking pan, sprinkle with salt and bake for about 15 minutes. Set aside. (Leave the oven set to 400 degrees.)
5. Heat 1 Tablespoon olive oil in a large skillet over medium-low heat. Cook the onion slices until tender. Season with a little salt.
6. Drain the steak in a colander, getting rid of any excess marinade. Heat 1 Tablespoon olive oil in a large skillet, over high heat. Once the pan is really hot, add the steak and brown just for a few minutes on both sides.
7. Place the baguette slices in the oven for just a few minutes, to lightly toast, without letting them get too crispy.
8. Spread a little of the horseradish mayo on each baguette slice, top with steak, onions, tomato slices and avocado. Serve immediately with lots of napkins.