Corned Beef Pot Pie

• 1 3 lb packaged corned beef
• ½ c salted Irish butter (such as KerryGold)
• 1 c chopped yellow onion
• 1 c chopped carrots
• 3 cloves garlic, minced
• 2 c chopped green cabbage
• 1 ½ c sliced baby red potatoes (about 8 oz. total)
• 1 ½ tsp kosher salt
• 1 tsp ground pepper
• 6 tbsp all-purpose flour
• 1 11.2 oz bottle stout beer, such as Guinness
• 2 c beef broth
• 3 tbsp whole grain mustard
• 1 9 oz roll-out pie crust, such as Jus-Rol

Prepare corned beef according to package directions with pickling spice in a Dutch oven. Remove beef from the pot to a cutting board to cool, and strain and reserve 2 cups of the cooking liquid. Discard remaining cooking liquid. Do not wash the Dutch oven.

Preheat oven to 400°F. Return Dutch oven to medium high heat, add butter, and cook until butter melts. Add onions and carrots and cook until softened, stirring often, about 6 minutes. Add garlic and cook until fragrant, about 1 minute more. Add cabbage, potatoes, salt, and pepper and cook, stirring often until cabbage softens, about 5 minutes. Sprinkle with flour, and cook stirring constantly for 1 minute. Add beer and bring to a boil. Cook, stirring constantly until liquid is reduced by half, about 3 minutes. Stir in reserved cooking liquid, beef broth, and mustard. Bring to a boil, lower heat to a simmer and cook, covered, until potatoes are just beginning to become tender, about 10 minutes.

Meanwhile, chop reserved corned beef into bite-sized pieces. Stir beef into vegetable and gravy mixture. Spoon mixture into a 12-inch cast iron skillet. Carefully unroll pie crust on a clean work surface and gently roll into a 12-inch circle. Transfer to the filled cast iron skillet, placing crust on top of filling. Place cast iron skillet on a foil-lined rimmed baking pan. Bake in preheated oven until golden and bubbly, about 15 minutes.

Allow to cool slightly, about 10 minutes, before serving.