In cold weather, potatoes are a Godsend. Baking them at high heat right on the racks slathered in olive oil and flaky sea salt not only makes for a tasty, crackly-skinned side, but fills my poorly heated apartment with radiating warmth. The act of mashing a big pot of them with a stream of buttermilk helps to maintain my illusion that this strenuous workout will combat the calories loaded in the extra helping I will inevitably devour (or at least keep my arms toned??). And crafting a casserole of potatoes au gratin, well, do I need a another reason to love this comfort food–browned and bubbly on top, warm and buttery beneath? I didn’t think so.
With cooler weather also comes prime apple-picking time and I always find myself with copious amounts of the crunchy fruit piled on my counter, overflowing from my cripser drawer. So as I sliced potatoes for a cheesy gratin last week, with a hunk of Gruyère and a block of Vermont cheddar waiting on the counter, I felt that bowlful of tart apples eyeing me reproachfully, chastising me for never getting around to that apple pie I wanted to bake. It occured to me then that the best attributes of apple pie, the sweet and slumpy fruit, would be exceptional tucked into cheesy herbed potatoes. And so it was settled. When I finished slicing the potatoes, I peeled and cored the apples and cut them to the same thickness (about 1/8 of an inch). A mandoline is ideal for this job; if you only have a very sharp knife and a steady hand, that works just fine. I made overlaping layers of the potatoes and apples in a shallow casserole dish, seasoning each layer with salt and cracked pepper, and then set my sights to the stove for the cheese sauce.
You can certainly use a number of different cheeses for this, but I like to use a mix of Gruyère and cheddar: Gruyère for that assertive, somewhat funky Swiss cheese flavor that settles in nicely with the earthiness of potatoes, and cheddar for its meltiness factor (technical term) and in this case, its perfect pairing with apples. I infused the milk with a sprig of rosemary and few sage leaves before adding the cheeses to melt. I would like to say at this point that I poured a perfect velvety cheese sauce over the potatoes and apples, slipped the casserole into the oven and calmly finished cooking the rest of my dinner while delicious aromas escaped from the oven. I repeat. I would like to say that is what happened. Reality isn’t always so kind, however. I won’t go into the nitty gritty awfulness of what ensued, but I will tell you that it started with a momentary distraction and ended with burn cream, a sink slick with oil and a strainer full of chunky cheese blobs. Thank you, Jon Hamm, for breaking my sauce.
I pride myself on being rather resourseful, so I did eventually remedy the mess I created. And the final product was most definitely worth all that effort. But word to the wise while making the sauce: maintain a gently simmering milk (don’t boil!) and, most importantly, do not let handsome comic actors steal your attention. Not even for a second. If you follow these simple rules, you will be pouring a perfect velvety cheese sauce over the potatoes and apples, slipping the casserole into the oven and calmly cooking the rest of your dinner while delicious aromas escape from your oven.
Apple Potato Gratin
2 Russet potatoes
2-3 of your favorite baking apples
1/2 small onion
1 c Gruyère cheese, grated
1 c white cheddar cheese, grated
1 c flour
1 1/2 c whole milk
1/2 tsp nutmeg (freshly grated, if you can)
1 sprig rosemary
2 sage leaves
salt and pepper to taste
Preheat oven to 375 degrees.
Peel and core the apples. Cut into 1/8 inch slices. Cut potatoes (I like to leave skin on, your choice) into 1/8 inch rounds. Alternating, lay the apples and potato slices in overlapping rings in a buttered (or Pam-ed) casserole dish. Salt and pepper each layer. Toss cheese with flour and set aside.
Place milk, rosemary, sage and nutmeg into a saucepan over medium heat. Grate the onion directly into the pan using the finest grater you have. You only want the flavor of the onion, not the texture. Let the sauce to come to a gentle simmer, (again, do not let it boil) and allow to simmer for about 5 minutes. Remove from heat and discard rosemary and sage. Add half the cheese and stir until it begins to melt. Add the remainder and stir until all the cheese has melted.
Pour cheese sauce over the potatoes. Cover with aluminum foil and bake until potatoes are tender, about 50 minutes. Remove the foil and allow to cook for another 10-15 minutes or until the top has browned.