For the chimichurri:
- 3 tablespoons Worcestershire sauce
- 1/4 cup red bell pepper, chopped
- 1 serrano pepper, seeded
- 1/2 small yellow onion
- 2 cloves garlic
- 1/2 cup parsley and cilantro, packed
- 1 sprig oregano or marjoram or 1 teaspoon dried oregano
- 2 pounds ground beef or pork
- Salt and pepper
For the toppings and fixings:
- 1 tablespoon canola or vegetable oil, plus some for drizzling
- 1 yellow onion, thinly sliced
- 1/2 pound white cabbage, cored and thinly sliced
- Salt and pepper
- 6 thick slices beefsteak tomato
- 1 cup mayonnaise/aioli, homemade* or store-bought
- 1/3 cup ketchup
- 1 tablespoon Worcestershire sauce
- 1/4 cup sweet pickle relish
- 6 burger rolls, club rolls or sweet Portuguese rolls, split
- Melted butter
*For the mayo/aioli:
- 1 egg yolk
- 1 rounded teaspoon Dijon mustard
- 1 tablespoon lemon juice
- 2/3 cup grapeseed oil
- Fine sea salt, to taste
Place the chimichurri ingredients in a food processor and fine chop into a thick sauce.
Place the meat in a bowl and season with salt and pepper. Add the chimichurri and combine. Form six patties and chill them for a few hours for the flavors to combine.
For the toppings, heat a skillet over medium-high heat with the oil. Add the onion and sweat a minute or two; add the cabbage, season with salt and pepper and let wilt for 2-3 minutes more. Remove from the heat.
Heat a griddle pan or cast iron skillet over medium-high heat with a drizzle of oil. Add the tomatoes; cook for a minute on each side, then remove to a plate. Brush the rolls with melted butter and griddle them until toasty and golden; remove to a plate. Add another drizzle of oil and cook the patties for 8-10 minutes.
If making your own aioli, whisk up the egg yolk, Dijon and lemon juice, then stream in the grapeseed oil slowly down the side of the bowl while whisking continuously; season with sea salt, to taste. Stir in the ketchup, Worcestershire, relish and combine.
Place the burgers on the rolls and top with onions and cabbage, tomato and some sauce.