In a large bowl, combine the ground beef, ground pork, salt, black pepper, cumin, paprika, and garlic powder. Mix until well combined, being careful not to overwork the meat.
Form the meat mixture into 8 equal-sized patties, about 1 inch thick.
Preheat a grill or grill pan over medium-high heat.
Grill the burgers for 4-5 minutes per side, or until cooked to your desired level of doneness.
During the last minute of cooking, place a slice of provolone cheese on top of each burger and allow it to melt.
Toast the burger buns on the grill or in a toaster oven.
To assemble the burgers, place a patty on the bottom half of each bun, top with a spoonful of chimichurri sauce, and cover with the top half of the bun.
For the Chimichurri Sauce:
In a medium bowl, whisk together the chopped parsley, cilantro, oregano, minced garlic, red wine vinegar, olive oil, salt, black pepper, and red pepper flakes.
Cover the bowl and refrigerate the chimichurri sauce for at least 30 minutes to allow the flavors to meld together.
Notes
Tips and Tricks
To prevent the burgers from puffing up while cooking, make a small indentation in the center of each patty with your thumb before grilling.Don't overwork the meat mixture when forming the patties, as this can lead to tough, dry burgers.Make the Chimichurri sauce ahead of time to allow the flavors to meld together and intensify.