Heat your griddle or cast iron skillet over high heat until it's smoking slightly. This is key — you want maximum heat to get that sear. I let mine preheat for at least 5 minutes before starting.

Portion your ground beef into 8 equal balls, about 2 ounces each. Don't overwork the meat or it'll turn tough and dense. Gently form each one without compressing it too much.

Place a ball on the hot griddle and immediately smash it flat with a spatula, pressing hard for 2-3 seconds. You'll hear it sizzle instantly — that's the sound of flavor developing. Hold the spatula down for just enough time to create that crispy crust, then flip.

The second side cooks way faster, taking only about 45 seconds. Top each patty with a slice or two of cheddar cheese right before this final flip so it melts into all the good crispy bits. I personally cover it with a lid for 10 seconds to speed up melting.

Meanwhile, butter those buns and toast them on the griddle until golden brown, about 1-2 minutes per side. Toast them right after the burgers come off so they're still warm when you assemble.

Spread mayo and mustard on the bottom bun. Layer lettuce, then your smashed patty with melted cheese, then tomato and pickles. Top with the onion and finishing bun.

Serve immediately while everything's warm and juicy. This 4th july smash burger cookout tastes best hot off the griddle, not after sitting around.