MadeGreat loose meat sandwich

Ingredients

• 1 cup flat leafed Italian parsley
• 1 cup cilantro leaves
• 1/2 cup fresh mint leaves
• 1 shallot, diced
• 4 to 5 cloves garlic, chopped
• 1/2 teaspoon red pepper flakes
• 3/4 cup olive oil
• 1/4 cup red wine vinegar
• salt
• pepper
• 2 large yellow onion or Vidalia onion, thinly sliced
• 2 tablespoons butter
• a pinch or more of kosher salt
• water
• 1 pound ground beef
• 1 1/2 tablespoon all-purpose flour
• 3/4 cup water
• 1 teaspoon salt
• 1 teaspoon ground black pepper
• 4 soft hamburger buns
• caramelized onions (from above)
• chimichurri (from above)