This stew can be made with any beer and any vegetables you might like to add. You'll need an 8-inch cast-iron skillet or baking dish. The stew can be made ahead and refrigerated, then baked at meal time. Allow the refrigerated stew to come to room temperature before baking.
In a large Dutch oven, heat 1 Tbsp. oil over medium-high heat. Add half the beef and cook, turning several times until seared. Remove to a plate. Add remaining 1 Tbsp. oil and brown the remaining beef and remove that to the plate as well.
Add onion and garlic to the pot and cook, stirring, until onion is softened. Add tomato paste and cook, stirring, for another minute. Add the beer, carrots and potato and 1/2 cup of the beef broth. Add the browned beef pieces. Stir to combine. Season with salt, pepper and spices. Bring to a boil, then reduce heat and simmer, covered for 30 minutes, or until beef and vegetables are tender.
After 30 minutes, combine the remaining 1/2 cup beef broth with the cornstarch and add to the pot. Cook uncovered, stirring, until sauce thickens. Spoon mixture in to an 8-inch cast-iron skillet or baking dish, place on a baking sheet and set aside to cool for 15-20 minutes.
Meanwhile, preheat your oven to 425° F. with rack in the centre of the oven. If your puff pastry is in a block, roll one block in to a square large enough to cover the top of your skillet, with a bit hanging over the edges. If desired, with the other sheet, roll into a rectangle and cut shapes from it using a leaf-shaped cookie cutter. When stew has cooled slightly, lay the rolled pastry sheet over top and then, if using, place the pastry leaves on top. In a small bowl, whisk together the egg with 1 Tbsp. of water and brush this mixture over the puff pastry.
Place in the oven (on top of the baking sheet) and bake for 15 minutes, then lower the oven temperature to 400° F. and bake for an additional 5-10 minutes until golden brown.
*Stew can be made ahead and refrigerated. Allow to come to room temperature before baking.
Be sure to read the “Ingredient and Cook's Notes" (above the recipe card!), where I share more detailedtips, variations and substitution suggestions for this recipe!