Chicken potpie, like so many other dishes, was a created as way to stretch chicken by encasing it in less expensive, more filling dough. In restaurants, the dish has gone through something of a renaissance, but not many people make it at home, maybe because it seems like too much work. This version is different, using a far simpler procedure. It is a chicken potpie reimagined as a cobbler, with less dough and more vegetables. The idea here is to do much of the cooking in one pot and skip the most finicky part, the crust, in favor of a simple biscuit topping. In about 45 minutes, you can have a hearty, savory cobbler that is, I’m almost sorry to say, as easy as pie.
Add stock and rosemary; bring to a boil, and let bubble for a minute or two, then add carrots and chicken and reduce heat so the liquid simmers. Cook until carrots are almost tender and chicken is cooked through, 8 to 10 minutes. Add peas and cook, stirring occasionally, until vegetables are brightly colored and just tender, another minute or so; remove rosemary stem and discard.
03In a small bowl, whisk cornstarch with a few tablespoons of water to make a slurry. Add slurry to pot and stir until liquid thickens slightly. Transfer everything to an ovenproof dish and set aside.
04Heat oven to 400 degrees. Put flour in a food processor with baking powder, soda and 1/4 teaspoon salt. Add butter and process until mixture resembles small peas, no more than 30 seconds. (You can also do this by hand, using two knives, a fork, your fingers or a pastry cutter). Transfer mixture to a bowl and mix in buttermilk and egg until it just comes together; it should be sticky.
05Drop spoonfuls of batter on top of vegetables and chicken and smooth with a knife, covering as much surface area as possible but leaving a few gaps for steam to escape. Bake for 35 to 45 minutes until golden on top and bubbly underneath. Scoop into bowls and serve immediately.