Add ground beef, salt and pepper, garlic powder, and grated Parmesan to a bowl.
1. Mix until well-combined.
Divide beef into 4 equally-sized balls and form into slightly flattened, round patties. Place on a plate and chill in the refrigerator.
Preheat oven to 400°F. Add bacon to a baking sheet lined with foil. If you have a baking sheet rack, use it to elevate the bacon.
Bake for 15-20 minutes, or until crispy to your liking. Drain on paper towels.
Prepare your caramelized onions.
Preheat grill or grill pan to high. If using a grill pan, lightly grease with oil. Place burger patties on grill once hot.
Turn after the first side no longer sticks to the grill. Cook burger patties to preferred level of doneness, using a meat thermometer to check the temperature (USDA recommends 160°F).
Top with avocado crema, bacon, cheddar cheese, lettuce, and tomato as desired. Serve on buns of your choice or leave out the buns for a keto-friendly dish.