First, form beef into patties. I recommend 1/4-1/3 lb patties. They should be about 1/2 inch in thickness. Season with salt & pepper. Set aside.
In a large skillet, over low to medium heat, melt 1 tbsp of ghee. Add onions & allow to saute for about 5 minutes. After 5 minutes, add 2 tbsp of water to the skillet & cover. Allow to cook for an additional 1 minute. Water should be completely absorbed & evaporated. Remove onions from the pan & set aside.
In the same skillet, add an additional tbsp of ghee. Once melted, add the hamburger patties. I like to flatten mine out a bit with a spatula upon placing them in the skillet. Allow to cook 4-5 minutes before flipping & cook for an additional 4-5 minutes or internal temp of 145° for medium wellness.
If making the burger sauce, mix the mayo, ketchup, mustard & syrup together now.
Before removing patties from the skillet, Top each burger with a spoonful of onions. top the burgers & onions with one slice of cheddar cheese. Cover Skillet & allow cheese to melt before removing the patties from the pan.
While the burgers rest, place hamburger buns in the skillet to soak up some of the juices & toast. About 1 minute.
Assemble burger with the bun, pattie, burger sauce & desired toppings. Ie. Lettuce, tomato, & pickle. Serve with a side of fries & enjoy!
Notes
For 4 people - separate meat into 1/4 lb patties. For 3 people, I would recommend 1/3 lb patties.