Prepare the Beef: Divide the lean ground beef into four equal portions, gently rolling each into a ball. Keep the beef cold until you're ready to use it.

Assemble the Tacos: Take a flour tortilla and place one beef ball in the center. Press down firmly to flatten the beef.

Heat the Skillet: Preheat a non-stick or cast-iron skillet over medium-high heat for about 2 minutes. Add oil and swirl to coat.

Sear the Tacos: Place the tortilla with the meat side down in the skillet. Press for about 2-3 minutes until browned and crispy.

Add Cheese: Flip the taco and place a slice of cheese on top of the meat. Cook until the cheese melts, about 1-2 minutes.

Finish the Tacos: Remove from skillet and top with diced onion, dill pickle chips, and lettuce.

Serve Hot: Serve immediately while hot and crispy, repeating for remaining beef and tortillas.