Stuffed shells with chicken, cauliflower and broccoli

Ingredients

• 340g giant shells
• 1 yellow onion, finely chopped
• 2 garlic cloves, finely chopped
• Olive oil
• 2 lb ground chicken
• 1 cup broccoli cut into small florets
• 1 cup cauliflower cut into small florets
• 3 tablespoons maple syrup
• 1/2 teaspoon Provence herbs
• 3 cups grated mozzarella cheese
• Salt and pepper from the mill
• 3 tablespoons butter
• 3 garlic cloves, finely chopped
• 3 tablespoons all-purpose flour
• 4 cups milk
• 1 1/2 cup finely grated parmesan cheese