Preheat your oven to 375°F (190°C).
Fit the pastry dough into a 9-inch quiche or pie pan, trimming the edges as needed.
In a large bowl, whisk together the eggs, half-and-half, salt, and pepper until well combined.
Spread the mozzarella cheese evenly over the base of the pastry.
Pour the egg mixture over the cheese layer.
Scatter the halved cherry tomatoes and basil leaves evenly over the top.
Bake in the preheated oven for 40 to 45 minutes, or until the custard is set and the top is golden brown.
Allow to cool slightly before slicing and serving.