Prepare the meatballs
In a medium bowl, combine half the chopped onion, 1/2 cup of cilantro, rice, eggs, two cloves of finely chopped garlic, mint if using, two teaspoons of oregano, 1 1/2 teaspoons of salt, one teaspoon of cumin, and 1/2 teaspoon of pepper. Mix in the ground beef gently until combined without overmixing. Form the mixture into meatballs, using about 1 1/2 tablespoons of mixture for each. Place the meatballs on a tray and cover until ready to use.
Tip: Wet your hands lightly to keep the meat mixture from sticking while forming the meatballs.
Cleanup: Wash your hands and any surfaces that touched raw beef immediately to keep the kitchen safe.