1. To make sauce, mix mayonnaise, pickles, pickle brine, ketchup, mustard, and garlic powder in a small bowl until combined; set aside.
2. Very gently shape beef into four loosely packed balls. Heat a large skillet over medium-high heat until very hot, about 5 minutes. Set a shallow bowl or pie plate filled with water next to stove.
3. Brush skillet with oil and add beef. Using a stiff metal spatula, press down firmly to form flat patties about 4" wide (edges will begin to break apart and get craggy). If spatula sticks to patties, dip it lightly in the water before pressing down.
4. Season flattened patties with salt and cook, without moving, until edges are deeply browned, about 3 minutes. Flip patties, season with more salt, and top with cheese. Continue to cook, without moving, until second side is deeply browned, about 3 more minutes.
5. To serve, transfer patties to bun bottoms and top with lettuce and tomato. Spread sauce on remaining bun halves and place on top.
Source: Hannaford fresh Magazine, May - June 2019