Bring the beef to near room temperature (15 minutes) and mince the garlic and slice the onion into thin half-moons. Warming the meat slightly makes it more co-operative when forming patties and helps it sear more evenly; slicing the onion thinly ensures fast, even caramelization.

Combine the ground beef, 1 tsp kosher salt, 1/2 tsp black pepper, 1 tsp smoked paprika, and 1/2 tsp dried thyme in a bowl. Gently fold with your hands 6–8 times — do not overmix. Seasoning the meat ahead distributes flavor; minimal handling keeps the patties tender by avoiding overworking the proteins.

Divide the mixture into four equal portions (~113 g / 4 oz each). Form each portion into a loose ball, then flatten into a 3/4"–1" thick patty with a shallow 1/2" dimple pressed in the center. The dimple prevents doming as the patty cooks, helping an even thickness and uniform doneness.

Preheat a heavy cast-iron skillet over medium-high heat for 4–5 minutes until smoking lightly. A hot pan is essential to create Maillard browning (the flavorful crust) quickly without overcooking the interior.

Add 1 tbsp neutral oil to the pan and immediately place two patties in the skillet, leaving space between them. Sear without moving for 3–4 minutes to develop a deep brown crust. Resist the urge to press the patties — pressing squeezes flavorful juices out and results in a drier burger.

Flip the patties and sear the second side for 2–3 minutes for medium-rare to medium (adjust 1–2 minutes longer for medium-well). Use an instant-read thermometer if you have one: target 125–130°F for medium-rare, 135°F for medium, 150°F for medium-well. Cooking times vary by pan and stove; the thermometer gives confidence and prevents overcooking.

While the second side sears, lower the heat to medium and push the patties to one side. Add the remaining 1 tbsp oil and 1 tbsp butter to the empty side of the skillet. Add the sliced onion and a pinch of salt. Cook, stirring occasionally, for 6–8 minutes until deep golden and soft. Caramelization is a slow process—patience yields sweet, nutty flavors that pair beautifully with beef.

Add the minced garlic to the onions for the last 90 seconds and stir to combine. The garlic will bloom quickly; adding it late prevents burning and provides fragrant aromatics.

Push the onions to the pan edge, return the patties to the center, then add the remaining 1 tbsp butter on top of each patty and spoon the melted butter and onions over the patties for 30–60 seconds. Basting with butter adds richness and glossy finish and helps meld the onion flavor into the meat.

Transfer patties and onions to a warm plate and let rest for 3–4 minutes. Resting allows juices to redistribute so the patty stays juicy when cut. Taste and adjust seasoning — add a small pinch of salt or pepper to the onions if needed.

To serve: place each patty on a warmed plate, spoon a generous amount of caramelized garlic-onion butter over the top and around the plate. If you have buns or toast, serve the patties on toasted buns with the onions as a topping. The focused presentation showcases the crust, butter sheen, and glossy caramelized onions—restaurant-style plating without fuss.