Rinse the meat under running water and dry. If there are films and veins on it, be sure to remove them, so it will marinate better and be softer. Wash vegetables and dry with paper towels. Peel the garlic.
In a deep container, mix salt, pepper and rosemary. Add mustard, garlic and honey, pour in beer. Make cuts in the meat, place in the marinade and refrigerate for several hours, or better yet, for a day. When the meat is marinated, bake it in the oven at 130°C for at least 3 hours.
Prepare the sauce; for this, chop the bell pepper and sun-dried tomatoes very finely, and also finely chop the greens. Place everything in a bowl, add chopped garlic and spices: oregano, red chili pepper, salt and black pepper. Pour in olive oil, regular and balsamic vinegar. Use a blender and blend until smooth. If desired, you can add more garlic and chili pepper to the finished sauce. who likes it spicy?
Place the finished meat on a plate in portions with chimichurri sauce and red peppers stuffed with cheese. Garnish the dish with lettuce leaves and serve.