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Show of hands – how many of you have ever tried rutabaga? How about fennel? Could you pick them out of a vegetable lineup? It’s ok, if you said no. Rutabagas are probably one of the most under-utilized root veggies out there. And fennel gets a bad rap — especially if you’re not a fan of aniseed flavors. But this gratin will change your mind about both of these maligned veg. Because this Tender Butternut Rutabaga Gratin is both savory and mildly sweet with a light crunchy topping and a cheesy interior. Skip the potatoes, this is what you want next to your Sunday roast chicken!
To make this dish, you need either a really good, sharp knife or a mandoline. I’ve done it with both, but I prefer a mandoline for perfectly sliced butternut, rutabaga and fennel. With a mandoline, you’re assured of even thicknesses – which makes your cooking time more accurate. If you’ve got some slices that are thicker than others, they’ll take longer to cook, right? A mandoline takes the guesswork out and it makes quick work of the vegetables.
If you don’t already have a mandoline, here’s a few links to check out. I have to be honest, I bought my mandoline for about $50 fifteen years ago — it’s lasted that long and is still in pristine condition, but a good one can be an investment. The upside is you only buy it once. Here’s one by OXO – it’s similar to mine in that you can set it over a cutting board and run the vegetable across the blade in a secure fashion, and this one from Kyocera is a hand-held model for about half the price. Not quite as sturdy — because you hold the handle with one hand while running the vegetable across the blade with the other. I prefer the first one, but its up to you.
The rutabaga and butternut squash are layered with melted leeks and fennel. Melted??? Sort of. The leeks and fennel are simmered with vegetable stock and herbs and reduced down to a syrupy – barely there – glaze. Tucked between the rutabaga and squash slices, the leeks provide just enough moisture to transform the root vegetables into fork-tender bites of goodness.
Of course, it wouldn’t be a gratin without cheese, and this one uses Gruyere – it’s French and it’s fabulous but Comte, Emmentaler or even Fontina are good substitutes. Bake the gratin in a casserole dish that’s tightly covered with tin foil for the first hour and fifteen minutes.
Then remove the foil and top with bread crumbs and dots of butter before you continue baking. In the end, you’ll have a bubbly, crispy, gooey gratin that you’ll come back to again and again.
- 1 small butternut squash, peeled and seeded
- 1 small rutabaga, peeled
- 1 leek, white and pale green parts only
- 1/2 bulb fennel
- 1 teaspoon fresh rosemary, minced
- 2 teaspoons fresh thyme, minced
- 1/2 teaspoon kosher salt
- 1/4 teaspoon black pepper
- 1 1/2 cups vegetable broth
- 1 cup grated Gruyere cheese (can also use Comte, Emmentaler or Fontina)
- 1 cup fresh breadcrumbs (whir a slice of bread in a mini prep food processor)
- 1 tablespoon butter, cut into small dice
- Preheat oven to 400 degrees.
- Lightly spray a large shallow baking dish.
- Fill a medium bowl halfway with cool water.
- Slice leek in half, vertically, then cut into 1/2" pieces crosswise. Transfer leeks to water and swish them with your hands to loosen any dirt. Dirt will fall to the bottom of the bowl, while leeks will float on top. Scoop the leeks from the surface of the water and transfer to a dry dish towel and pat away the excess water.
- Heat a small pot over medium heat and add 2 tablespoons olive oil. Add leeks and fennel and cook until they are softened, about 5 minutes. Stir in rosemary, thyme, salt, pepper and vegetable broth. Bring to a boil, then reduce heat to simmer and cook for 10-15 minutes until broth has reduced to 3/4 cup or about half.
- Slice the squash and rutabaga into very thin rounds. (You can use a mandoline, the slicing attachment on a food processor or a very sharp knife).
- Place 1/3 of leek mixture and broth into the bottom of the baking dish. Arrange butternut squash and leeks in an overlapping layer. Scoop 1/3 of leeks and broth over the vegetables and sprinkle with half of the cheese. Top squash with another layer of squash and rutabaga, followed by the remaining leek mixture and cheese.
- Spray a piece of aluminum foil with vegetable spray, cover the gratin (sprayed side down) tightly with foil and bake for 1 hour and 15 minutes (this will prevent the cheese from sticking to the foil). Remove the foil, sprinkle with the bread crumbs. Dot the top of the gratin with the butter and continue to bake for 15 more minutes, until top of the gratin is crisp and brown. Let the gratin rest for 5-10 minutes before serving.