Sweet Potato and Swiss Chard Gratin


I realize that by this point most of you already know exactly what you’ll be making for dinner this Thursday – whether you’re in charge of an entire Thanksgiving meal for 20, or just picking up a pie on your way to dinner. But in case anyone is in need of last minute ideas for sweet potatoes or veggies (I think this dish could fall into either category), I wanted to post this gratin that I made for a “practice Thanksgiving” a couple weeks ago. It’s from Smitten Kitchen, again – I promise that after this I really am going to start getting more creative with the blogs I copy recipes I share. I’ve been wanting to try this for the past few years, however, and since I finally made it, I thought it might inspire the few of you that are still looking for inspiration.

Full disclosure, I’m still debating what I’m going to be making – and I have to start grocery shopping tonight. As much as I love the old school sweet potatoes with brown sugar and marshmallows, about 90% of my relatives prefer a savory sweet potato dish like this one, so I’m going to be making a couple different casseroles (Grandma and I need our marshmallows!). Another favorite is this scalloped sweet potato and yukon gold casserole, which people go nuts for. If anyone has a favorite sweet potato recipe, sweet or savory, I would love to hear it in the comments.


My mandoline will be a year old tomorrow – it was a birthday gift last year and I love it even more now than I did when I received it. It makes the thought of potato casseroles for 45 so much less daunting.


The swiss chard is a pain to prep (wash, de-stem, chop), and made even more complicated because this recipe calls for the stems to be used as well – just separated from the leaves as they have to cook longer. They’re good for us, though, and if you use rainbow chard it looks so pretty!! I’m thinking of subbing spinach when I make it this time, just to save myself about three hours of chopping and stemming effort. You could use any green you like, I think – my friend Kirsten tried it with collard greens, which is even more Thanksgiving-y.


But the rainbow chard stems are really pretty – and surprisingly delicious.



Simply sauté the chard stems with a little diced onion, then add the greens, which will cook down significantly (I cut this recipe in half when I made it for practice Thanksgiving, and the raw chard filled my 5 quart Dutch oven; once cooked it was barely two cups of greens).


A pile of grated Gruyère always makes me happy.  This is probably more than the recipe called for, oops! Five ounces, eight ounces, who’s counting? Not me.  It is Thanksgiving, after all.


Layer: potatoes, herbs, cheese, chard, béchamel; repeat.  I’m starting to get concerned that all of my grocery stores are going to be out of fresh thyme again – I feel like it happens every year, and every year I swear I’m going to stock up ahead of time – and then forget to do so.  I couldn’t find fresh thyme when I made this the other week, so I just used dried (with fresh parsley) – but I bet it will be even better with the fresh thyme that I’m hopefully going to find tonight (fingers crossed).


A little more cheese, and it’s all ready for the oven.  SK says (and I hope she’s right!!) that this can be prepped ahead of time, and just baked on Thursday, or fully baked ahead of time and then re-heated before your meal, assuming you have oven space.  Oven space is a hot commodity when you have a large group in a non-commercial kitchen, so neither option is ideal for me, but I’m just going to worry about that on Thursday.  The good news is a gratin will stay pretty hot.


Sweet Potato and Swiss Chard Gratin, from Smitten Kitchen

Serves 12

1/4 cup (1/2 stick) unsalted butter
1 small onion, finely chopped
3 lbs swiss chard, leaves and stems separated and both cut into one-inch pieces
Pinch of freshly grated nutmeg
2 cups heavy cream or whole milk
2 garlic cloves, minced
2 tablespoons flour
2 lbs medium sweet potatoes or yams, peeled and cut into 1/8-inch thick rounds
1 tablespoon minced fresh Italian parsley
1 tablespoon minced fresh thyme
Fine sea salt
Freshly grated black pepper
1 1/4 cups (about 5 ounces) coarsely grated Gruyère cheese

Prep greens: cook onion in two tablespoons butter in a large pot or Dutch oven over moderately low heat, stirring, until softened. Add chard stems, nutmeg, and salt and pepper to taste and cook, stirring, until vegetables are browned, about 8 minutes. Increase heat to moderately high and add chard leaves by large handfuls, stirring, until all greens are wilted. Season with salt and pepper and then transfer to a colander and press out liquid with a rubber spatula or large spoon.

Make sauce: combine cream or milk and garlic in a small saucepan and bring to a simmer; keep warm. Melt two tablespoons butter in a heavy saucepan over moderate heat and stir in the flour. Cook roux, whisking, for one minute, then slowly whisk in cream/milk and bring to an almost-boil, whisking constantly, for one minute longer. Season sauce with salt and pepper.

Assemble gratin: Preheat the oven to 400 degrees F. Butter a 9 x 13 baking dish. Spread half of the sweet potatoes in the prepared dish and sprinkle with salt, pepper, and a quarter of the herbs and a quarter of the cheese. Distribute half the greens mixture over the cheese, then sprinkle salt, pepper, a quarter of the herbs and a quarter of the cheese over that. Pour half of the bechamel sauce over the first two layers and then continue with the remaining sweet potatoes, more salt, pepper, herbs, and cheese, and then the remaining chard mixture, salt, pepper, and herbs. Pour the remaining sauce over the top of the gratin and then sprinkle with the remaining cheese.

Bake gratin: bake the gratin for about one hour, until golden, bubbly, and most of the liquid is absorbed. Let stand for ten minutes before serving.

Do ahead: you can make the entire gratin but not bake it up to a day in advance (just store it in the fridge). You can also make and bake it in advance, and reheat it, though it will take almost as long to reheat as they do to bake in the first place.

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