In a large bowl, combine lean ground beef, egg, dried parsley, grated onion, minced garlic, sea salt, and pepper. Mix gently with your hands until just combined, then let it rest for 15 minutes.

Divide the meat mixture into seven or eight equal portions, shaping each into a small patty. Create a slight indentation in the center of each patty.

Thinly slice your onions. Heat a skillet and add butter or olive oil. Once melted, add onions, stirring occasionally, and cook for 15-20 minutes until caramelized.

Increase skillet heat to medium-high. Cook the sliders for about 3-5 minutes on each side until browned and cooked to a minimum internal temperature of 160°F.

Once cooked, let them rest. Assemble sliders with a patty on each bun, topped with caramelized onions and any favorite toppings.

Serve immediately with sweet potato fries or salad, allowing everyone to build their own sliders.