Place the bay leaves and thyme on a small piece of cheesecloth and tie the corners together tightly to form a bundle; set aside.
Heat 3 tablespoons vegetable oil in a large pot or Dutch oven over medium-high heat. Season the beef with 2 teaspoons salt and 1 teaspoon pepper. Working in batches, add the beef to the pot and cook, turning, until browned all over, about 5 minutes. Transfer to a plate and add the bacon to the pot. Cook, stirring occasionally, until browned and crisp, about 5 minutes. Add the carrots, onion and garlic and cook, stirring occasionally, until tender, about 5 minutes. Add the tomato paste and cook, stirring, until the vegetables are coated, about 1 minute. Add the flour and cook, stirring, 1 minute.
Add the cognac to the pot and cook, scraping up any browned bits, until the liquid has mostly evaporated, about 1 minute. Add the wine, chicken broth, cheesecloth bundle, browned meat and any juices and bring to a boil. Reduce the heat to medium, cover and simmer, stirring and scraping up the bottom of the pot occasionally, until the beef is tender and the sauce is thick, about 2 hours. Discard the cheesecloth bundle.
Meanwhile, make the crust: Combine the flour and 1 1/2 teaspoons salt in a food processor and pulse to combine. Add the parsley and chives and pulse to combine, then add the butter and pulse 8 to 10 times until it looks like coarse meal. Add 1/2 cup ice water and pulse until the dough just starts coming together, adding 1 to 2 tablespoons more ice water if necessary. Turn the dough out onto a large piece of plastic wrap and form into a disk; wrap and refrigerate 30 minutes or overnight.
Preheat the oven to 400 degrees F. Finish the stew: Heat the remaining 1 tablespoon vegetable oil in a large skillet over medium-high heat. Add the mushrooms, 1/2 teaspoon salt and a few grinds of pepper. Cook, stirring occasionally, until the mushrooms are lightly browned, about 7 minutes. Add to the pot with the stew along with the pearl onions and butter; stir. Transfer the mixture to a 3-to-4-quart oval or 9-by-13-inch baking dish and set aside to cool.
On a lightly floured surface, roll out the dough into a 12-by-15-inch rectangle, about 1/8 inch thick. Beat the egg with 1 tablespoon water; brush the edges and outside of the baking dish with the egg wash. Drape the dough over the filling and press it against the sides of the dish; trim any excess to leave a 1-inch overhang. Cut a few slits in the top to vent.
Brush the crust with more of the egg wash. Bake until the crust is golden brown and the filling is bubbling, about 45 minutes. Let rest 10 minutes before serving.
Photograph by Justin Walker
Freeze it! Make the potpie until the end of the step for cutting the slits on top to vent. Tightly wrap in foil and freeze up to 3 weeks. Brush the dough with an egg wash (1 egg beaten with 1 tablespoon water) and bake at 375 degrees F from frozen, about 1 1/2 hours.
Courtesy of Food Network Magazine