Adapted from my new Gourmet Today cookbook (thanks, Mom!). This is true comfort food.
1 1-pound package frozen pearl onions (not thawed)
2 1/2 cups water
3 tablespoons unsalted butter
1 fresh thyme sprig, plus 1 teaspoon chopped fresh thyme
Salt and freshly ground pepper
1 medium onion, coarsely chopped
3 carrots, coarsely chopped
2 celery ribs, coarsely chopped
1 large parsnip, peeled and coarsely chopped
1 medium boiling potato, peeled and coarsely chopped
10 ounces white mushrooms, trimmed and quartered
Any other veggies: sweet potatoes, turnips, squash, etc., coarsely chopped
1 garlic clove, minced
2 tablespoons all-purpose flour
1 cup milk
1/4 cup white wine (optional)
1 (10-ounce) package frozen peas, thawed
For biscuit topping
2 1/4 cups all-purpose flour - I used a mix of white and white whole-wheat
2 teaspoons baking powder
1 teaspoon baking soda
3/4 teaspoon salt
1/4 teaspoon freshly ground pepper
3/4 stick (6 tablespoons) unsalted butter, cut into 1/2-inch cubes and chilled
1 cup coarsely grated extra-sharp cheddar (about 4 ounces)
3 tablespoons finely grated Parmigiano-Reggiano
1 1/2 cups well-shaken buttermilk or yogurt
1. Combine pearl onions, water, 1 tablespoon butter, thyme sprig, 1/2 teaspoon salt, and 1/4 teaspoon pepper in a 2-quart heavy saucepan and bring to a boil. Reduce heat and simmer, covered, until onions are tender, about 8 minutes. Drain in a sieve set over a bowl; reserve liquid and discard thyme sprig.
2. Meanwhile, heat the remaining 2 tablespoons of butter in a 12-inch deep heavy skillet over moderately high heat until foam subsides. Add chopped vegetables, mushrooms, garlic, chopped thyme, and 1/2 teaspoon salt and cook, stirring occasionally, until vegetables begin to brown (bottom of skillet will become crusty), about 15 minutes.
3. Sprinkle vegetables with flour and cook, stirring, for 1 minute. Add reserved onion cooking liquid and milk (and wine, if using) and bring to a boil, stirring and scraping up brown bits. Reduce heat to moderate and simmer, covered, until vegetables are barely tender, about 10 minutes.
4. Remove from heat and stir in peas, pearl onions, and salt and pepper to taste. Pour into a 9x13-inch baking dish.
5. Put a rack in the middle of the oven and preheat to 450F. Whisk together flour, baking powder, baking soda, salt, and pepper in a large bowl. Blend in butter with your fingertips or a pastry blender until mixture resembles coarse meal. Stir in cheeses, add buttermilk or yogurt, and stir just until combined.
6. Drop biscuits onto filling in 12 equal mounds, leaving spaces in between. Place baking dish on a foil-lined baking sheet and bake until topping is golden and filling is bubbling, 25-30 minutes. Let stand for 5 minutes before serving.