Smash Burger Patty Melts Recipe (with Video)

1. To cook our onions, slice our onions lengthwise. Next, in a large skillet, add in 2 tablespoons of butter on medium-low heat. Once butter is melted, add in sliced onions and mix in with melted butter and oil. Cook slowly and stir occasionally for about 10 minutes or until onions become softened. Add in a pinch of salt and finish cooking for about 2 minutes and set aside.
2. To cook our burgers, form ground beef into about ¼ pound balls. In a cast iron skillet at medium-high heat, add in neutral cooking oil of choice. Once oil is hot, add in beef and smash down. If you do not have a non-stick smasher, you can cover the burger ball with a piece of parchment paper and use a flat surface utensil and smash it down. Season with salt, black pepper, & garlic powder or with spices of choice. Then, cook for a couple of minutes until the bottom side is cooked and flip over. Cook until the bottom side is just about cooked, add on cheese, cover, and cook until the bottom side is cooked, cheese is melted and burger is cooked to preference.
3. For burger sauce, in a bowl, combine and mix well mayo, ketchup, dill relish, white vinegar, Worcestershire sauce, white sugar, garlic powder, and black pepper. Optional, you can add salt to taste after mixing if you would like.
4. Assemble patty melts as you desire.
5. To toast patty melts, in a skillet on medium-low heat, add in 2 Tablespoons butter. Once butter is melted, add in the assembled patty melt. Toast on each side for a couple of minutes, or until both sides are golden brown.