This dish is part of our pub fare menu.
Preheat oven to 400°. Line a large baking sheet with parchment. Cut puff pastry into six disks; arrange on sheet. Bake in upper third of oven until golden, 5 to 8 minutes. Cool on a wire rack.
Season beef and kidneys with salt and pepper. Heat a large, heavy skillet over medium-high heat; add oil. Working in 2 to 3 batches, sauté meat, turning occasionally, until just browned. Cook each batch 5 to 8 minutes; remove with a slotted spoon and set aside. Reduce heat to medium; add shallot, carrot, and celery to skillet. Sauté until vegetables are tender, stirring frequently, about 6 minutes. Stir in flour and cook, stirring constantly, 1 minute. Return meat to pan, and slowly stir in stock. Bring to a boil, stirring frequently, then stir in butter. Season with salt and pepper; add thyme.
To serve, divide stew among 6 bowls and top each with a puff pastry disk.
Chef Armstrong recommends pairing this dish with a Bordeaux.