Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add 1 diced onion and sauté for about 3-4 minutes until translucent. Stir in 2 minced garlic cloves and cook for 1 more minute.

Add 1 pound of ground beef to the skillet and break it up. Cook for 5-7 minutes, stirring occasionally, until browned. Drain excess fat if necessary.

Once browned, sprinkle in taco seasoning and pour in 1/4 cup of water. Stir, bring to a simmer, and let cook for 5 minutes until the sauce thickens. Adjust salt and pepper to taste.

In a large bowl, combine 4 cups of chopped romaine lettuce, 1 cup of halved cherry tomatoes, 1 can of rinsed black beans, and 1 cup of corn. Toss gently to mix.

Top the salad base with the warm beef mixture. Add 1 cup of shredded cheddar cheese, 1 diced avocado, and 1/2 cup of sour cream. Finish with salsa and chopped cilantro.

Serve your Beef Taco Salad immediately or chill in the refrigerator for about 30 minutes if preferred.