1
Combine all the ingredients of the tzatziki dip, mix well, and refrigerate for at least 30 minutes.
3
Melt feta cheese on the griddle for about 40 seconds to get crispy on the bottom but stay creamy on top.
4
Top each smash burger patty with crispy feta cheese.
5
Assemble the burger by placing a bed of arugula, a slice of heirloom tomato, and a patty on the bottom bun, then topping with tzatziki dip and finishing with the top bun.