- 2 cups (packed) baby kale or baby spinach
- 1 pound ground sirloin
- 3 to 4 tablespoons grated onion with juices
- 1 tablespoon Worcestershire sauce
- Salt and pepper
- 1 tablespoon olive oil
- 4 slices Cooper sharp white American cheese or Monterey Jack
- 1 ripe Hass avocado, pitted and peeled
- 3/4 cup sour cream
- 2 tablespoons chopped fresh chives
- 2 tablespoons chopped fresh dill
- 2 tablespoons chopped fresh parsley
- Juice of 1/2 lemon (about 2 tablespoons)
- 1 large clove garlic, grated
- 1 tablespoon green hot sauce (such as Tabasco Green Jalapeño Pepper Sauce)
- 4 brioche rolls, split and toasted
- Lettuce, tomato and thinly sliced onion
In a food processor, pulse the greens until very finely chopped.
In a mixing bowl, combine the greens and the meat. Add the onion and its juice, and the Worcestershire; season with salt and pepper. Form into 4 patties that are thinner in the centers for even cooking. Rinse out the processor bowl and return it to the base.
Heat a cast-iron skillet over medium-high. Add the oil, one turn of the pan. Add the patties and cook, turning occasionally, until browned, about 8 minutes. During the last minute or so of cooking, top each patty with 1 slice of cheese; tent loosely with foil to melt the cheese.
In the processor, combine the avocado, sour cream, herbs, lemon juice, garlic and hot sauce. Season with salt and process into a smooth, thick dressing.
Serve the patties on the rolls with the lettuce, tomato, onion and lots of dressing.