A bright and cheery combination of turnips, rutabagas, and carrots baked with creamy, buttery white sauce and topped with crispy bread crumbs.
- 1 medium yellow onion; 4 slices reserved, the rest finely chopped (3/4 C chopped)
- 1 medium carrot, diced
- 1/3 C diced celery (1 small stalk)
- 5 to 10 thyme sprigs, tied into a bundle
- 5 to 10 whole black peppercorns
- 2 C whole milk
- 5 T unsalted butter, divided (plus more for dish)
- 3 1/2 T all purpose flour
- 1/2 C heavy cream or half and half
- 3 1/4 t kosher salt
- 1/2 t ground white pepper
- Freshly grated nutmeg (or dried; see notes)
- 3/4 lb. rutabaga, peeled and julienned
- 3/4 lb. turnip(s), peeled and julienned
- 3 medium carrots, peeled and julienned
- 1 C fresh bread crumbs (my method in notes to this recipe)
- 1 T olive oil (plus more for dish, if not using butter)
- Heat a large pot of water over high heat, while you prepare the béchamel. If it boils before the sauce is finished, turn down the heat slightly so it will return quickly to a boil later.
- Combine onion slices, carrot, celery, thyme, peppercorns, and milk in a small saucepan and heat over medium low. Once warm, gradually raise heat until milk just boils, then remove from heat and set aside, covered. In a medium saucepan, melt 4 tablespoons butter over medium heat, then add flour and stir or whisk constantly for a few minutes as it bubbles slightly. Reduce heat to medium low and carefully whisk while pouring in milk with all its additions. Once combined, raise heat to medium high and bring to a simmer. Stir, simmering, for a couple minutes, until slightly thickened. Reduce heat to low and stir frequently, ensuring that no flour accumulates in the corners of the pan, for about 15 minutes. Set a mesh strainer over the pan used to heat the milk, and pour sauce through it, stirring to encourage all the sauce through the strainer (which may take a few minutes; see notes for alternatives to straining). Stir in cream, then season with 1/2 to 3/4 teaspoon salt, 1/4 teaspoon pepper, and a pinch of freshly grated nutmeg. Set aside sauce.
- Add 1/2 tablespoon salt to now-boiling water. Lower rutabagas only into water, maintain high heat, and blanch for 2 minutes (water may not return to a boil in that time). Drain rutabaga and rinse briefly with cold water.
- Preheat oven to 375 degrees (F). Melt 1 tablespoon butter in a medium skillet over medium heat. Add diced onion and cook until softened, but barely browned, about 8 minutes. Place onion in a large bowl and add blanched rutabaga, turnip, carrot, 1 teaspoon salt, and 1/4 teaspoon pepper (or more seasoning to taste). Toss to combine.
- Lightly grease a deep, 8 by 10 inch (or thereabouts) casserole pan or baking dish with butter or oil. Distribute the vegetable mixture in an even layer. Pour béchamel evenly over vegetables, spreading gently with back of a spoon to cover, if needed. Top with a layer of all the bread crumbs, then drizzle with a tablespoon of olive oil. Bake on middle oven rack for 45 minutes, until bubbling and top is slightly golden. Cool 5 to 10 minutes before serving. Leftovers keep well in the refrigerator for a few days. See notes for make ahead instructions.
If you don’t have the time or tools to strain the béchamel, either use entirely edible, finely chopped aromatics (onion, carrot, celery, garlic) or flavor the milk with a bay leaf and bouquet garni of peppercorns and thyme, removing both just before adding milk to the roux.
To substitute ground nutmeg, start with the smallest pinch possible, tasting and adding more if needed.
To assemble up to 12 hours (or more?) in advance, leave breadcrumbs and oil off until ready to bake and refrigerate in baking dish, covered. Bring to room temperature for an hour before baking, to keep approximately the same cook time. If baking straight from the fridge, add 10 or more minutes, and make sure the gratin is heated through.
- Prep Time: 65 mins
- Cook Time: 45 mins
- Category: Vegetarian
- Cuisine: Seasonal