If you’ve never combined turnip and parsnip with potatoes, you’re in for a treat. The sweet parsnip and sharp turnip elevate this potato dish to a whole new level. While tasty, it also cuts the richness from the cheese and cream in the dish just enough to ease any guilt you may have for eating something so delicious.
It’s that easy: I started adding parsnip and turnip to mashed potatoes about 20 years ago and loved how it made them even more savory, so it made sense to start adding them to potato casseroles as well. Other potato-friendly add-ins are celery root and rutabagas. Just be sure to cut all the vegetables to the same thickness so that everything cooks at the same rate.
- Cook time:
- Prep time:
- Total time:
- 1 tablespoon unsalted butter
- 1 teaspoon fresh thyme, minced
- 2 teaspoons Dijon mustard
- 2 cups heavy cream, plus more if necessary
- 1/2 cup milk, plus more if necessary
- 1 teaspoon salt
- Freshly ground black pepper
- 2-lbs Yukon Gold potatoes, peeled, halved and very thinly sliced
- 1/2-lb parsnips, peeled and very thinly sliced
- 4-oz turnip, peeled, halved and very thinly sliced
- 8-oz Gruyére cheese, grated
- Preheat an oven to 400°F
- Butter a 2-quart casserole dish and set it aside.
- In a large saucepan, combine the thyme, mustard, cream, milk, salt and pepper to taste and bring to a simmer.
- Combine all the vegetables in a large bowl and arrange evenly in the casserole dish. Carefully pour the hot cream mixture over the vegetables and top with the cheese. The potatoes should be immersed in the liquid. If they are not, pour in a touch more cream or milk. Cover with non-stick foil and transfer the dish to the center rack in the preheated oven. Bake for 40 minutes or until the potatoes are super bubbly and almost tender.
- Remove the foil and continue to bake another 20 minutes or until tender (poke it with the tip of a sharp knife to test) and the top is browned. It will look soupy, but the potatoes will absorb the liquid as it sits. Rest at least 15 minutes, covered with the foil before serving.
- The casserole can be held, covered for up to 30 minutes or it can be assembled a day ahead and baked as directed. If baking cold from the refrigerator it will take 10 minutes longer to cook.