Preheat the oven to 220°C (425°F) and line a large baking sheet with parchment paper.
Heat vegetable oil in a skillet over medium heat; sauté the onion, garlic, and ginger until the onion is translucent.
Add curry powder and salt to the skillet, stirring constantly for 60 seconds to toast the spices.
Stir in the diced chicken, peas, and heavy cream. Simmer for 3 to 5 minutes until the sauce has thickened and coats the chicken thoroughly.
Remove the mixture from heat and allow it to cool for at least 10 minutes to prevent the dough from tearing.
Divide the pizza dough into 4 equal portions and roll each into a circle approximately 20cm in diameter on a lightly floured surface.
Place 1/4 of the chicken mixture and 1/4 of the mozzarella cheese onto one half of each dough circle, leaving a 2cm border around the edge.
Fold the dough over the filling and press the edges together, crimping with a fork or fingers to create a tight seal.
Transfer the calzones to the prepared baking sheet, brush the tops with the beaten egg wash, and cut a small steam vent in the center of each.
Bake for 18 to 20 minutes until the crust is deeply golden and sounds hollow when tapped.