1. Preheat a large cast iron skillet or griddle over medium-high heat. You want it hot enough to create a nice sear but not so hot that it burns the meat instantly.
2. While the pan is heating, divide the ground beef into 4 equal portions and loosely form each into a ball—don’t pack them too tight. Season each ball generously with salt and pepper.
3. Brush the croissant halves lightly with melted butter and set aside.
4. Add the vegetable oil to the hot pan, then place the beef balls onto the skillet, leaving enough room between them.
5. Using a sturdy spatula or the bottom of a heavy pan, smash each ball down firmly to about 1/4-inch thickness. The thinner, the better for that crispy edge. Let them cook undisturbed for 2-3 minutes until the edges are golden and crispy.
6. Flip the patties carefully and immediately place a slice of cheese on each. Cook for another 1-2 minutes until cheese melts and patties are cooked through.
7. While the patties cook, toast the buttered croissant halves on a separate pan or in the oven at 350°F for about 3-4 minutes until golden and flaky.
8. In a small bowl, mix mayonnaise and Dijon mustard. Spread this on the bottom half of each croissant.
9. Assemble your burger: mayo-mustard spread, crisp lettuce leaf, cheesy burger patty, pickle slices, and thin red onion slices. Top with the croissant crown.
10. Serve immediately while the croissant is warm and the burger juicy. My kids love it with a little extra ketchup on the side—always a winner.

Here’s a little secret from my experience: don’t skip the smashing. It’s what gives you those crispy edges that make every bite so satisfying. And if your skillet isn’t cast iron, just make sure it’s heavy-bottomed to get that perfect sear.