Gently mix the ground beef with salt, pepper, smoked paprika, and garlic powder in a bowl, being careful not to overwork the meat for tender patties.
Divide the mixture into four equal portions and gently form each into a patty about 3/4 inch thick, making a small indentation in the center of each to prevent puffing up during cooking.
Heat your cast iron skillet over high heat until very hot, with a slight smoke and a faint sizzle when a drop of water hits the surface.
Place the patties in the skillet, spaced apart, and cook for about 3-4 minutes without pressing down, until a deep golden crust forms and the meat releases easily from the pan.
Flip the patties using a spatula, and cook for another 3-4 minutes until a crust forms on the other side and the internal temperature reaches 71°C (160°F).
During the last minute of cooking, place a slice of cheese on each patty if using, allowing it to melt slightly.
Remove the patties from the skillet and let them rest for 2 minutes, allowing the juices to redistribute.
While the burgers rest, lightly toast the buns in the skillet or a toaster until golden and crisp.
Spread spicy mayonnaise on the bottom bun, then layer with lettuce, a slice of tomato, pickles, and the rested burger patty with melted cheese.
Cap with the toasted top bun, give the burger a gentle press, and serve immediately with your favorite side.
