Caramelize the onions

• Heat a little oil in a frying pan over medium-low heat.
• Add the sliced onions with a pinch of salt and cook slowly, stirring often, until soft and golden.

Make the burger sauce

• Mix the mayonnaise, ketchup, dijon mustard, chopped pickles and smoked paprika in a bowl.
• Season with salt and pepper and set aside.

Prepare the garlic butter

• Mash the softened butter with the minced garlic and chopped parsley.
• Spread the garlic butter over the cut sides of the buns.

Toast the garlic bread buns

• Place the buttered buns cut side down in a pan or under the grill.
• Toast until golden and crisp at the edges.

Smash and cook the patties

• Heat the pan until very hot and add the beef balls.
• Smash each ball flat with a spatula and season with salt and pepper.
• Flip the patties once browned and top with the cheddar slices to melt.

Assemble the burgers

• Spread burger sauce on the toasted garlic bread buns.
• Layer the patties with caramelized onions and close the burgers.
• Serve immediately.