Ingredients
4-5 medium carrots, peeled, halved lengthwise, and cut into 3/4-inch chunks
1 1/2 pounds button mushrooms, trimmed and halved or quartered if large
1 1/2 pounds yukon gold potatoes, cut into 1-inch chunks
3 large parsnips, peeled, halved lengthwise, and cut into 1-inch chunks
1 pound leeks, white and pale green parts only, sliced into 1/2-inch half-moons and washed well
1/4 cup olive oil
3/4 teaspoon dried thyme
Coarse salt and ground pepper
3 cups canned reduced-sodium vegetable broth
1/2 cup dry red wine
2 tablespoons cornstarch dissolved in 1/3 cup water
2 to 2 1/4 cups all-purpose flour, plus more for work surface
2 1/4 teaspoons baking powder
3/4 teaspoon baking soda
1/2 teaspoon salt
1/4 teaspoon ground pepper
6 tablespoons cold unsalted butter, cut into small pieces
3/4 cup buttermilk
3/4 cup shredded cheddar cheese
Preparation
Preheat oven to 425 degrees. Make filling: In a bowl, toss vegetables with oil and thyme; season generously with salt and pepper. Divide between two rimmed baking sheets. Roast 25 minutes; toss (if vegetables are sticking, sprinkle up to 1/4 cup water on each sheet). Roast until browned and tender, 20 to 25 minutes more. Transfer to a shallow 3-quart baking dish. Raise oven heat to 450 degrees.
Meanwhile, make topping: In a large bowl, whisk together 2 cups flour, baking powder, baking soda, salt, and pepper. Cut in butter with a pastry blender until mixture resembles coarse crumbs, with some pea-size lumps. Mix in buttermilk and cheese until combined. With a floured hand, knead dough against side of bowl until it holds together. If it is sticky, knead in up to 1/4 cup more flour.
In a small saucepan, bring broth and wine to a boil. Whisk in cornstarch mixture; boil 1 minute. Pour over vegetables; toss to coat. Drop small mounds of topping on vegetables; bake until brown, 15 to 20 minutes. Let cool 10 minutes; serve.
