In a large pot, boil 4 cups water. Using tongs, dip each cabbage leaf in water for 30 seconds and place on a paper towel lined plate to dry.
In a large bowl, combine ground beef, panko bread crumbs, about half the green onions, egg, garlic, and 1 teaspoon sesame oil. Season with salt and red pepper flakes. Scoop heaping tablespoons of mixture and roll into balls.
In a large skillet over medium-high heat, heat vegetable oil. Add meatballs and sear until each side develops a crust, about 2 minutes per side or until the internal temperature reaches 145°. Remove meatballs from skillet, and add remaining teaspoon sesame oil. Stir in ginger and cook until fragrant, about 30 seconds. Add chicken broth, soy sauce, and brown sugar. Bring to a simmer then return meatballs to skillet and add carrots. Cover with lid and cook until meatballs are cooked through and carrots are crisp-tender, about 10 minutes more.
Garnish with remaining green onions and sesame seeds. Serve warm in cabbage leaves.
Recipe by The Best Video Recipes for All at https://recipes-for-all.com/mongolian-meatball-cabbage-cups/