Chicken Alfredo pasta shells

• 16 giant shells
• 15 ml (1 tbsp) canola oil
• 3 small skinless chicken breasts cut into cubes
• 1 chopped onion
• 500 ml (2 cups) baby spinach
• Salt and pepper to taste
• 125 ml (1/2 cup) grated parmesan
• 125 ml (1/2 cup) grated mozzarella
• 30 ml (2 tbsp) minced fresh basil

For the Alfredo sauce

• 625 ml (2 1/2 cups) 15 % cooking cream
• 10 ml (2 tsp) cornstarch
• 125 ml (1/2 cup) white wine
• 1 chopped onion
• 5 ml (1 tsp) minced garlic
• 250 ml (1 cup) grated parmesan
• Salt and pepper to taste