Months ago, on a Saturday afternoon long before the freak Halloween snowstorm arrived and knocked our power out for several days, we happened to drive by a road side farm stand. The farm stand was set on a gravel lot next to a corner car dealership. There were half a dozen 4 x 4 foot wood crates filled with the usual winter squash suspects: blue hubbard, buttercup, butternut, sugar pumpkin. There were palates stacked with yellow onions and bins with green and red peppers and green and purple cabbage too. But, when I saw the fifty-pound bag of potatoes, I saw every sort of potato dish that would get us through winter. As the one vegetable everyone in the house eats, I was thrilled. I bought one large sack of the Yukon Golds and for a moment, contemplated a second.
Last weekend, I decided to dig into the bag and make a potato gratin. I brought my favorite chartreuse green plastic bowl (left at my apartment years ago at a potluck) downstairs and filled it with a pound of potatoes. The supply has dwindled down to about ten pounds or so which at this point is good, a few too many have sprouted eyes and have grown soft to the touch. The winter before when we hauled a winter storage share down to the corner pantry, the carrots and cabbage didn’t make. So I had my reservations about composting another heap of rotten smelly vegetables.
The woman at the stand was spot on. We put the potatoes on a basement shelf stored inside the ventilated paper sack they came in and with the exception of a few gnarly softies; they survived.
Also, I recently learned from my mom who has worked in a number of large kitchens, that if you individually wrap each potato in newspaper, then slip them back into their sack that the paper wrapping prevents the whole bag from rotting if one happens to go. A good tip for us New England dwellers to keep in mind for next winter’s haul.
This gratin recipe is a riff off one I usually make from Bon Appétit for Thanksgiving and occasionally Easter dinner. It employs a similar technique of layering a mix of thinly cut sweet and Yukon Gold potatoes with cheese, salt, and pepper. Next add a layer of cream sauce goes on top and repeat those steps. I suppose that’s where the similarity ends. I came up with a leek and shallot cashew cream seasoned with fresh ground nutmeg along with parsley and thyme leaves. I also use a tofu-based cream cheese in this one, but dairy would be just as nice.
The cashew cream sauce imparts an unexpected richness that I hope you’ll like. We certainly did as the empty dish in the kitchen sink can attest to—if it in fact could speak.
One of the keys to this recipe is to get the potatoes sliced paper-thin with the slicing blade in a food processor or with a mandolin. If neither are available, use the slicing side of a box grater or a sharp knife and try to cut them in even thin slices so they cook evenly and nearly melt into the sauce. The other is the leek and shallot cashew cream sauce. As I the sauce warms in the pan, I like to add the seasonings to taste adding a pinch more salt, a few more thyme leaves, or extra black pepper. I recommend you do the same.
Yukon Gold and Sweet Potato Gratin with Leek & Shallot Cashew Cream Sauce
Makes 4 to 6 hearty servings
3 cups thin cashew cream (1 cup raw cashews ground to a powder then blended in a food processor or blender with 2 cups of water)
2 tablespoons olive oil plus more for baking dish
¼ cup sliced leeks (rinse, cut into rounds, wash in a bowl of water, drain)
¼ cup finely chopped shallots
freshly ground black pepper
1 pound sweet potatoes, peeled and thinly sliced
1 pound Yukon Gold potatoes, peeled and thinly sliced
1/8 teaspoon ground nutmeg
2 sprigs chopped fresh thyme leaves
2 tablespoons chopped fresh parsley leaves plus more for garnish
1 ½ cups cream cheese (use your favorite tofu or dairy-based brand, divided)
½ chopped sunflower seeds
Preheat the oven to 375º F. Oil a 3-quart baking dish.
Combine the peeled and sliced potatoes and place in a large bowl of water to prevent the potatoes from browning; set aside.
To make the cashew cream, grind the cashews to a powder in a food processor or a high speed blender, add the water and blend until smooth and creamy; place the cream in a medium size saucepan and gently warm it over low heat.
While the cream warms up, heat the oil in a skillet over medium heat. Add the leeks, shallots, and a pinch of salt and pepper and a splash of water; stir and cook for about 5 to 7 minutes until tender, then add them to the saucepan of warm cashew cream. Season the cream with nutmeg, black pepper, the fresh thyme and parsley leaves. Add a few pinches of salt, taste, and adjust the seasoning if needed.
Drain the potatoes, then pat them dry with a kitchen towel. Layer half the potatoes on the bottom of the gratin dish; sprinkle with sea salt and black pepper. Using a teaspoon, scoop the cream cheese then dot the potatoes layer evenly with half the cream cheese. Pour half the cashew cream sauce over the potatoes. Repeat with another potato layer, followed by the other half of the seasoning, cream cheese, and cashew cream sauce. Sprinkle the chopped sunflower seeds evenly over top.
Place the gratin on the middle oven rack and bake, undisturbed until the potatoes are tender when pierced with a knife and the top is browned, about 55 minutes to 1 hour. Garnish with chopped parsley leaves and serve right away or keep warm in the oven.