For the Chimichurri Sauce – 1/2 cup flatleaf parsley – 1/2 cup fresh cilantro – 1 shallot roughly chopped – 1 jalapeno seeded and finely chopped – 4 cloves garlic minced – 1/2 cup white vinegar or fresh lime juice – 1 Tbsp fresh oregano chopped – 2/3 cup olive oil – ¼ teaspoon black pepper – ¼ to 1/2 teaspoon red pepper flakes optional – 1 tsp sea salt to taste Beef Sliders: – 1 pound ground beef – 2 Tbsp chimichurri sauce + more for serving – 6 to 8 slices Pepper jack cheese – 1 large ripe avocado sliced – Mixed green – 6 to 8 slider buns toasted