Chicken parm meatballs

Ingredients

• 1 1/4 lbs ground chicken
• 1/2 cup dried bread crumbs
• 3 tbsp finely chopped onion
• 2 tbsp chopped fresh parsley
• 1/2 cup grated parmesan , or pecorino
• 1 garlic clove
• 1 tsp fennel seeds
• 1 egg , whisked
• grated lemon zest , from 1/2 lemon
• salt and pepper , to taste
• 3 tbsp olive oil
• 1 14-ounce can store-bought pizza sauce , (such as Don Pepino's)
• 4 ounces fresh mozzarella cheese , in thin slices