FRENCH ONION PENNE WITH CHICKEN MEATBALLS AND ZUCCHINI

Ingredients

• 1 stick butter
• 3 pounds onions, sliced into thin rounds (about 4-5 large onions)
• 1 tablespoon sugar
• 1 ½ teaspoons salt
• 1 tablespoon Worcestershire sauce
• 2 tablespoons cornstarch
• ½ cup red wine
• 2 cups beef stock
• 2 tablespoons fresh thyme leaves, stemmed (plus stems for garnish)
• 2 slices white bread
• ⅓ cup milk
• 2 pounds ground chicken
• 2 eggs, beaten
• 6 cloves garlic, finely chopped
• 1 cup shredded Jarlsberg cheese (or good quality Swiss)
• 2 teaspoons salt
• 1 teaspoon black pepper
• 1 teaspoon dried thyme
• 1 cup panko breadcrumbs
• ½ cup Italian breadcrumbs
• ½ cup grated parmesan cheese
• ½ cup fresh parsley, chopped
• 3 tablespoons olive oil
• 2 tablespoons olive oil
• 4 garlic cloves, chopped
• 1 medium to large zucchini, cut into ½” thick half moons
• 1 pound penne pasta, cooked al dente to package directions
• 4 cups baby spinach leaves, packed
• 2 cups shredded Jarlsberg cheese (or good quality Swiss), plus more for garnish