Indian Samosa Pie

Name: Indian Samosa Pie
Ingredients: 0.5 cup all-purpose flour; 0.5 cup whole-wheat pastry flour; 0.25 teaspoon salt; 2 tablespoons vegetable oil; 6 tablespoons ice-cold water, or more as needed; 1.25 pounds potatoes, peeled and quartered; 1 tablespoon black or yellow mustard seeds; 1 teaspoon curry powder, or more to taste; 1 teaspoon ground ginger; 0.5 teaspoon ground cumin; 0.125 teaspoon red pepper flakes; 1.5 teaspoons vegetable oil; 1 cup diced onion; 0.5 cup diced carrot; 1 tablespoon minced garlic; 1 cup low-sodium vegetable broth; 1 cup frozen peas; 2 teaspoons white sugar; salt and ground black pepper to taste; 2 tablespoons milk