Superstar chef Bobby Flay serves this sweet poato biscuit-crusted chicken pot pie on the lunch menu at his New York City restaurant Bar Americain.
Preheat the oven to 375 degrees. Prick the sweet potato several times with a fork, place on a baking sheet, and roast in the oven until soft, about 45 minutes. Remove from the oven and let cool slightly. When cool enough to handle, halve the potato lengthwise and, using a small spoon, scrape the flesh into a medium bowl; discard the skin. While the potato is still hot, mash with a potato masher or fork until slightly smooth. Measure our 1 cup potato.
Stir together the flour, salt, and pepper in a large bowl. Cut in the butter until the butter pieces are the size of small peas. Stir together the egg, milk, and sweet potato in a bowl, add the mixture to the flour, and gently mix with a rubber spatula until just combined. Transfer to a lightly floured surface and lightly knead the dough until it just comes together. Form into a circle and flatten slightly. Wrap in plastic wrap and refrigerate until chilled, at least 1 hour or overnight.
Preheat the oven to 375 degrees.
To make the filling, melt the butter in a medium saucepan over high heat. Add the diced onion and cook until soft, about 4 minutes. Add the garlic and cook for 1 minute. Add the flour and cook, stirring occasionally, until deep golden brown, about 3 minutes. Slowly whisk in the hot milk and cook until thickened, 5 minutes. Reduce the heat to medium and cook, whisking occasionally, for 5 minutes. If the mixture is too thick to pour easily, thin it with a little extra milk.
Add the mushrooms, turnips, carrots, pearl onions, peas, chicken, and chipotle purée to the sauce and fold gently to combine. Season the sauce with salt and pepper and stir in the parsley. The filling can be made a day in advance, covered, and refrigerated.
For individual servings, divide the dough in half and roll each half out on a lightly floured surface until 1/8 inch thick. Invert individual ovenproof bowls onto the rolled crust and, using a sharp knife, cut circles around the outside of the bowls that are slightly larger than each bowl. Fill the bowls 3/4s of the way with the chicken mixture, making sure each serving has a nice amount of chicken, vegetables, and sauce. Carefully cap each crock with a pastry round, pressing the dough around the rim to form a seal. Brush the tops with the egg wash and season with salt and pepper. Make a small slit in the center of each using a paring knife. Alternatively, roll one large crust and use it to top a family-style pot pie in a 10-inch baking dish.
Transfer the pies to baking sheets and bake until the crust is golden brown and the filing is bubbly, 15 to18 minutes for individual pot pies and 25 to 30 minutes for 1 large pot pie. Remove from the oven and let sit for 5 minutes before serving.