Cooking Root Vegetables

Most of us are familiar with carrots and potatoes, but what to do with celeriac, turnips, parsnips, and rutabaga? The good news is that cooking root vegetables is pretty standard. Roast them, or cook them in water to make a puree for soups, or as an elegant bed for a vegetable slaw and small amount of meat protein. Remember, you can mix several different kinds together, but try to cook sweeter types (rutabagas, parsnips, and carrots) and bitter types (celeriac or celery root and turnips) together. You can also mash root vegetables with potatoes and cooked cauliflower to expand the flavor and vitamin profile.

1. Wash vegetables. If possible, give the vegetables a good scrubbing and cook with the skin on, as that is where most of the vitamins are. If you want a more elegant presentation, peel the vegetables with a vegetable peeler.

2. Cut vegetables into pieces; the size depends on the final use. A 1/4-1/2” dice works well if want to toss the root vegetables with pasta, serve them as a side dish, or add them to soup. If you are going to puree them into a sauce or mash them with other vegetables, you can save a little time and cut them into larger pieces. Cut the vegetables so they are fairly uniform in size, so they cook evenly.

3. Roasting
Preheat oven to 425 degrees F. Toss the vegetables with olive oil, salt, pepper and a little garlic and roast until tender and brown (about 30-60 minutes). Roast a combination of root vegetables at the same time for a range of colors, textures, and flavors.

4. Boiling and Mashing/Pureeing
Put the vegetables in a saucepan and cover with cold water until the vegetable are just covered. Do not cover the saucepan. Bring to a boil, then lower to a simmer, and cook until tender (about 5-20 minutes, depending on the size of the pieces). Mash the vegetables manually with a potato masher and mix with milk, a little butter and salt (to taste). You can also puree the vegetables in a blender or food processor with a little stock and/or milk to make a sauce or soups. Pureed vegetables are also a healthy way to thicken soups and stews.

5. Gratin
Gratin is a culinary technique in which an ingredient is bound together with some milk or cream, and then topped with a browned crust, typically breadcrumbs, grated cheese, egg and/or butter. The starch in potatoes helps bind the gratin together, and mellows the taste of bitterer root vegetables. Try combining celeriac and turnips with potatoes to mellow their flavor. Parsnips have a mild flavor and high starch content and can be cooked on their own.

Cut vegetables into thin pieces (about 1/8 – 1/4”). Uniform-sized pieces are important, so the vegetables cook evenly. You can use a food processor with a thin slicing blade, but the pieces will not be very uniform. A    mandoline is highly recommended.

Use just enough liquid (milk or cream) so that all but the top layer is covered: when you press down, the liquid should come up and barely cover the top layer. A combination of half milk and half cream is best; if you use too little cream, the milk may curdle and the vegetables may develop a grainy texture. For a leaner gratin, you can substitute broth for part of the milk or cream.. It is best to spread one layer of vegetables, season with salt and pepper, drizzle with liquid, and repeat, so that each layer is seasoned.

Top with cheese. Gruyère or Parmigiano Reggiano are good, but Parmigiano Reggiano is best if you want a crisp crust. Sprinkle with bread crumbs, if desired, and bake at 375 degrees F until the mixture is bubbling, but no longer soupy, and the top is golden brown. It is best to use a thin and wide dish, so that you have more surface area with that wonderful crispy, caramelized gratin crust.