Cut the puff pastry sheet into squares and bake for 10 minutes until puffed and golden.
Meanwhile, heat oil in a large saucepan over medium heat. Sweat the onion and add zucchini, carrot and garlic (optional), stirring for 5 minutes or until soft.
Add mince. Cook for three minutes or until the mince changes colour.
Stir in tomato, tomato paste and water and simmer for 5 minutes.
Split each pastry square to separate the top from the bottom. Top the bottoms with bolognaise mixture and cheese and bake for 3 minutes.
Top with the remaining pastry tops and serve (with a green salad if desired)