Cod Potpie with Dill Biscuits

1/2 cup finely diced onion

1/2 cup finely diced carrot

1/4 cup finely diced celery root

3 tablespoons unsalted butter

2 tablespoons all-purpose flour

1 1/2 cups whole milk

3/4 teaspoon salt

1/4 teaspoon black pepper

1 1/4 pounds skinless cod fillet, cut into 3/4-inch chunks (or 1/2 to 3/4 pounds cod plus 2 small-to-medium potatoes, peeled, diced, and boiled for about 5 minutes)

For biscuits:

1 1/2 cups all-purpose flour

1 tablespoon baking powder

3/4 teaspoon salt

7 tablespoons cold unsalted butter, cut into 1/2-inch cubes, plus 1 tablespoon, melted

1/2 cup plus 1 tablespoon whole milk

2 1/2 tablespoons chopped fresh dill

Put oven rack in middle position and heat oven to 450°F.

Cook onion, carrot, and celery root in 3 tablespoons butter in a 2- to 3-quart heavy saucepan over moderate heat, stirring frequently, until tender, about 7 minutes. Add flour and cook, stirring, 1 minute. Stir in milk, 1/4 teaspoon salt, and 1/8 teaspoon pepper. Bring sauce to a boil, stirring, then reduce heat and simmer, stirring occasionally, 4 minutes. (Sauce will be thick.) 

Sprinkle cod with remaining 1/2 teaspoon salt and 1/8 teaspoon pepper.  Add fish to simmering sauce, then remove pan from heat.  

To make biscuits, whisk together flour, baking powder, and salt in a bowl. Blend in butter cubes with your fingertips or a pastry blender until mixture resembles coarse meal. Stir in milk and dill with a fork until mixture just comes together. Gather dough into a ball, then turn out onto a lightly floured surface and knead 2 or 3 times. Roll out with a floured rolling pin into an 8-inch square (1/2 inch thick), then cut out biscuits.

Fill small-to-medium pie dish or baking dish or individual ramekins with fish mixture, and top with biscuits.  Brush tops of biscuits with melted butter.  Place in oven and bake until sauce is bubbling and biscuits are golden, 12 to 15 minutes.

Serves 4.

From Gourmet via Epicurious with some changes