BBQ beef flank steak with balsamic reduction and cheese toasts

Ingredients:

For the sauce and steak:

• 1.5 cups balsamic vinegar
• 2 tablespoons of vegetable oil
• 1 small onion, coarsely chopped
• 1 large clove of garlic, coarsely chopped
• 1/2 cup ketchup
• 1 tbsp ancho chili seasoning (poblano)
• 1.5 tsp paprika
• 2 teaspoons Dijon mustard
• 1.5 tsp red wine vinegar
• 1.5 tsp Worcestershire sauce
• 1 small chipotle chili pepper in adobo sauce, chopped
• 1.5 tsp dark brown sugar
• 2 teaspoons of honey
• 2 teaspoons of molasses
• Coarse salt and freshly ground pepper
• 900 g of beef flank

For toast:

• 1 French baguette, cut in half lengthwise, then cut into 10cm long pieces.
• Olive oil
• Coarse salt and freshly ground pepper
• 1 tbsp. grated cheese Monterey Jack
• Sliced ​​green onions, for sprinkling

Preparation:

1. Prepare balsamic sauce: In a saucepan, bring the balsamic vinegar to a boil and cook over medium heat until reduced by half, 15 to 20 minutes. Remove from heat.
2. Heat 1 tablespoon vegetable oil in a skillet over medium-high heat. Add the onion and cook until softened, 3 to 4 minutes. Add the garlic and cook for 1 minute. Add the ketchup and 3 tablespoons water and bring to a boil. Reduce the heat and simmer for 5 minutes.
   
   Add boiled balsamic vinegar, chili powder, paprika, mustard, red wine vinegar, Worcestershire sauce, chipotle peppers, brown sugar, honey, and molasses. Continue to simmer, stirring occasionally, for another 10 minutes, until thickened.
3. Puree the sauce with an immersion blender or transfer it to a blender and puree until smooth. Season with salt and pepper. Transfer the sauce to a bowl and cool to room temperature. The sauce can be stored in an airtight container for up to 1 week. If the sauce becomes too thick after storage, dilute it with 1-2 tablespoons of water.
4. Remove the meat from the refrigerator 30 minutes before cooking and let it come to room temperature. Meanwhile, preheat the grill to high. Brush the beef with the remaining vegetable oil and sprinkle with salt and pepper.
   
   Grill the steak over direct heat until browned on one side, about 3 minutes, then flip and continue cooking, about 3 more minutes, until browned on the other side. Move the steak to a cooler part of the grill, away from direct heat. Baste with the sauce and continue cooking, turning several times, until medium-rare, about 5 more minutes. Transfer the beef to a cutting board and cover loosely with foil. Let rest for 10 minutes.
5. Meanwhile, prepare the cheese toasts: Brush the cut sides of the bread with olive oil and sprinkle with salt and pepper. Fry on both sides. Transfer the toasts to a sheet of foil and sprinkle with cheese. Place under the grill and continue cooking until the cheese melts. Place the toasts on a serving platter.
6. Slice the steak thinly across the grain. Place the meat on toast and sprinkle with green onions.