• Start by making the balsamic grilled onions. Melt butter in a pan over medium heat. Once it begins to bubble, add the diced onions, brown sugar, and a pinch of salt. Cook until the onions are fragrant and begin to soften. If they start sticking to the pan, deglaze with 1–2 tablespoons of water at a time. After about 5 minutes, pour in the balsamic vinegar and continue cooking until the onions are caramelized and the sauce is thickened.
• For the burgers sauce: Combine mayo, ketchup, mustard, relish, onion powder, garlic powder and smoked paprika. Mix until well combined. Season with salt and pepper, if desired. Taste and adjust to your liking if needed.

for the burger

• Bring ground beef to room temperature and form into balls placing them on separate pieces of parchment paper. Heat cast iron skillet or pan over medium high heat. Add in 1 tsp of oil and 1 tbsp of unsalted butter.
• Toast the buns for 2-3 minutes, until golden.
• Place a ground beef ball onto a hot pan and let it sit for 20 seconds before pressing it down firmly with a burger press. Remove the parchment paper and cook for 2-3 minutes. While cooking, season the exposed side with salt, pepper, and a drizzle of yellow mustard, if desired.
• Flip the burger, season the other side with salt and pepper, and cook for another 2 minutes. Add a slice of cheese, reduce the heat, then add a splash of water and cover to steam the cheese until melted—about 45 seconds. Repeat these steps if you're making a double cheeseburger.
• To assemble: Spread burger sauce on the bottom bun, then add one patty and a spoonful of grilled onions. Top with the second patty, another layer of onions, more sauce, and finish with the top bun. Serve with fries and enjoy!