Butter 6 3/4- to 1-cup capacity ramekins and set aside. Bring a medium pot of salted water to a boil. Add the frozen vegetables and potato, return to a boil, then reduce heat and cook for 4 minutes. Drain and set aside.
Melt the butter in a large heavy pot over medium heat. Add the onion and celery and sauté for 5 minutes. Add the flour and curry powder, and cook, stirring, for 1 minute. Stir in the vegetable broth and coconut milk. Continue cooking, stirring often, until thickened, about 5 minutes.
Stir in the tomatoes and vegetables. Season with salt and pepper. Cook 2 minutes, then remove from heat and set aside. Heat the oven to 375 degrees.
On a lightly floured surface, roll out the pie crust and cut a round to fit the top of each ramekin, rerolling as needed. Evenly distribute the filling among the ramekins and place them on a large, parchment-lined baking sheet. Top each ramekin with a dough round and brush it lightly with the egg wash. Bake until the pastry is golden brown, about 40 minutes. Let cool for at least 15 minutes before serving.
