Caramelize the onions: In a large skillet over medium heat, melt the butter. Add the sliced onions and sugar. Stir occasionally until the onions are deeply caramelized and sweet, which should take around 20 to 25 minutes. If the onions get a bit sticky, add a splash of beef broth to help deglaze the pan.

Prepare the burger patties: While your onions are working their magic, season the ground beef with salt, pepper, and Worcestershire sauce. Now, form that seasoned beef into 4 equal-sized patties, ready to be cooked.

Cook the burger patties: Place the patties in a skillet or on a grill and cook until they reach your desired level of doneness. The beauty is that you can have them just how you like.

Assemble the burgers: If you want to elevate your burgers, prepare garlic butter buns. Simply spread a mixture of butter and minced garlic on the buns and toast them until golden. On each bun bottom, nestle a cooked burger patty, layer on those caramelized onions, and top with a slice of cheese.

Broil to perfection: Once assembled, pop them under the broiler for a few minutes until the cheese is melted and bubbly. Oh, the aroma will be divine!

Finish and serve: Sprinkle fresh thyme over the cheese, place the bun tops on, and serve immediately to your eager diners!