This hearty minestrone comes with a multitude of meatballs! To avoid toughening meatballs, use your hands for mixing meatball ingredients and SHAPE GENTLY when forming the meatballs.
Meatballs: Place bread in large bowl. Moisten with 1/4 cup (50 mL) of the broth. Let stand 5 minutes. Using fork, stir to form paste. Add ground beef, salt, pepper, ½ tsp of the Italian seasoning and half the garlic. Gently work together. Shape into about twenty-five 1-inch (2.5 cm) balls; cover and refrigerate. Make ahead: cover and refrigerate for 1 hour or up to 1 day.
Cook onion, remaining garlic, carrot, celery, remaining Italian seasoning, and chili pepper flakes (if using) in Dutch oven, stirring occasionally over medium-high heat until vegetables soften, about 5 minutes.
Add tomatoes, broth and tomato sauce; bring to boil. Drop meatballs into sauce; reduce heat, cover and simmer for 15 minutes.
Add kale and pasta; simmer for 10 minutes or until pasta is tender.
Skip making the meatballs, and brown ground beef while cooking the onion.