"Rachael Ray's Provolone-Stuffed Meatballs with Kale"

Ingredients

• ½ cup dry breadcrumbs or panko breadcrumbs
• ⅓ cup whole milk
• 1 lb. ground beef (80% lean)
• Salt and pepper
• 1 scant tbsp. Calabrian chile paste or 1 tsp. crushed red pepper
• 2 large cloves garlic, grated or finely chopped
• 1 tsp. (1/3 palmful) fennel seeds
• 1 cup (packed) baby kale; or 1 cup (packed) stemmed Tuscan kale, blitzed in a food processor until finely chopped
• 1 cup (loosely packed) grated Pecorino Romano (about 2 oz.)
• 1 egg, lightly beaten
• 2 to 3 oz. provolone, cut into 1/2-inch cubes
• Olive oil cooking spray, or olive oil for brushing