The key to a better burger: Crust is king!
Smashed burgers share the same thin, verging-on-well-done profile and all-American array of condiments as typical fast-food burgers, but their big selling point is an ultra-brown, crispy crust. We used commercial ground beef instead of grinding our own, because the former is ground finer and thus exposes more myosin, a sticky meat protein that helps the patties hold together when they are smashed.
Using a small saucepan to press straight down on the meat ensured that it spread and stuck uniformly to the skillet (instead of shrinking as it cooked), which helped guarantee deep browning. We made two smaller patties at a time instead of one larger one, because they fit nicely inside a burger bun.
Sandwiching a melty slice of Kraft American cheese between the two patties helped the cheese melt thoroughly and seep into the meat almost like a rich, salty cheese sauce would. Our creamy, tangy burger sauce added more richness and moisture; lettuce and thinly sliced tomato provided freshness and acidity; and the soft bun offered tenderness.
For the sauce:
2 tablespoons mayonnaise
1 tablespoon minced shallot
1 1/2 teaspoons finely chopped dill pickles plus 1/2 teaspoon brine
1 1/2 teaspoons ketchup