Finely chop the rosemary, garlic, and basil. Wash the lettuce and chop it. Chop the tomatoes. Peel the avocado, cut into strips, and immediately drizzle with lemon juice to prevent browning.
Put the beef and pork in a bowl. Add the chopped rosemary, basil, and garlic. Mix well and refrigerate until ready to cook.
Divide the meat into 4 equal portions of roughly 150 grams each. Shape each into a patty. Heat oil in a large pan over medium-high heat. Fry each patty for 2-3 minutes per side until the internal temperature reaches 71 °C / 160 °F. Optionally fry the bacon strips in the same pan until crispy.
Toast the burger buns lightly if desired. Spread barbecue sauce on the bottom half of each bun. Place a patty on top, then add tomato, lettuce, and avocado slices. Close with the top bun and serve.