Gently mix the seasonings into the beef with your hands just until combined — do not overwork. Divide into 4 equal portions (about 4 oz each). Form each portion into a patty roughly 3/4-inch thick and about 4 inches in diameter, making a slight dimple in the center of each patty with your thumb to reduce puffing while cooking.

Cook patties

Heat a large skillet or cast-iron pan over medium-high heat. Add 1 teaspoon vegetable oil and swirl to coat. When the pan is hot and shimmering, add the patties leaving space between them. Cook undisturbed for 3–4 minutes until a brown crust forms. Flip and cook 2–3 minutes more for medium (adjust time for desired doneness). In the last minute of cooking, place a slice of cheddar on each patty and cover the pan briefly to melt (about 30–60 seconds). Remove patties to a plate and let rest for 2 minutes.

Buns & Toppings

Prepare vegetables

While the patties cook, slice the tomato into 1/4-inch thick slices, thinly slice the red onion into rings, and separate/clean lettuce leaves. Set aside pickles.

Toast buns

Spread softened butter evenly on the cut sides of the hamburger buns. After removing the patties from the pan (while pan is still hot), place buns butter-side down in the skillet and toast over medium heat until golden brown, 1–2 minutes. Remove buns.

Assemble burgers

Spread about 1 tablespoon mayonnaise on the bottom half of each bun, then 1 tablespoon ketchup and 1/2 tablespoon mustard (adjust to taste) on top of the mayonnaise or on the top bun as preferred. Place a lettuce leaf on the dressed bottom bun, add a cheese-topped patty, add a tomato slice, a few onion rings, and two pickle slices. Top with the bun crown and press lightly.

Serve

Serve immediately while hot with optional sides (fries, chips, or salad).