Directions

• Preheat oven to 400°F. Heat oil in a 10-inch cast iron skillet over medium until shimmering. Add onion, carrots, and potatoes; cook, stirring frequently, over medium until carrots and potatoes are just starting to soften, 4 to 5 minutes. Stir in garlic and ginger; cook stirring constantly until fragrant, about 1 minute.
• Add stock and bring to a boil over medium-high, stirring occasionally; reduce heat to medium-low and simmer, stirring occasionally and adjusting heat as needed, until vegetables are fork tender, 8 to 10 minutes. Stir in curry mix, ketchup, and salt until dissolved and mixture is thickened, about 2 minutes. Stir in chicken until evenly distributed. Remove from heat and keep warm.
• Roll pastry on a lightly floured surface into a 13-inch square. Lay pastry over skillet; trim leaving a 3/4- to 1-inch overhang. Fold pastry under itself so rolled edge is flush with top edge of skillet; use the tines of a fork to crimp edge into side of skillet. (It’s OK if pastry doesn’t perfectly adhere.)
• Brush top of pastry with beaten egg. Cut 8 (1 1/2- to 2-inch) slits in top of pastry to vent.
• Bake until pastry is golden brown and filling is bubbly, about 30 minutes. Let stand 15 minutes before serving.