In a small bowl, make the burger sauce by combining the mayonnaise, ketchup, dijon mustard, pickle juice, garlic powder, and smoked paprika. Season with salt and pepper to taste and set aside.
Divide the beef mince into 8 equal portions and roll each into a ball. Season the balls with salt and pepper.
Heat a large cast iron pan or flat-top grill on high heat until it's very hot. Place a beef ball into the pan and immediately press it down with a spatula or burger press to flatten it, using a piece of baking paper between the meat and spatula. You want it to be very thin (about 1 cm thick).
Let the burger cook undisturbed for 2-3 minutes, allowing it to develop a crispy crust.
Flip the burger, add a slice of cheese on top, and cook for another 1-2 minutes until cooked through.
While the burgers cook, toast the burger buns in a separate pan or on the grill until golden.
Assemble the burgers by spreading a generous amount of the homemade burger sauce on the bottom bun. Add two of the burger patties, followed by your toppings such as lettuce, tomato, and pickles. Top with the other half of the bun.
Serve immediately with extra burger sauce on the side for dipping, if you like.