In a medium saucepan, bring the vegetable broth to a boil. Add the rinsed quinoa, cover, and reduce to a simmer. Cook for about 15 minutes or until the quinoa is fluffy and the liquid is absorbed. Remove from heat and let it sit covered for 5 minutes before fluffing with a fork.
In a bowl, combine the chopped parsley, cilantro, minced garlic, red pepper flakes, olive oil, and vinegar. Season with salt and pepper to taste. Mix well and set aside for flavors to meld.
Season the flank steak with olive oil, salt, and pepper. Heat a grill or cast-iron skillet over medium-high heat. Cook the steak for about 4-5 minutes per side for medium-rare, or until desired doneness. Let the steak rest for 5 minutes before slicing thinly against the grain.
In serving bowls, start with a base of quinoa. Top with sliced steak, cherry tomatoes, avocado, corn, red bell pepper, and a generous amount of chimichurri sauce drizzled over everything.
Sprinkle chopped cilantro over the top for added freshness. Serve immediately with extra chimichurri on the side for those who want more flavor.
Notes
Adjust the spice level of the chimichurri sauce to your preference.