Tater Time (part 2)
Scalloped Potatoes with Mushrooms, Onions, and Ham
Back in December I wrote a post about my love for potatoes (including recipes for the best mashed, roast, and pan-fried potatoes,) so if you missed that one, you can go back in read it. I still maintain that potatoes are one of the greatest, most nutritious, and most versatile ingredients in cooking. For people who are gluten intolerant or have Celiac, they can be the backbone of so many dishes that might otherwise use wheat-based pasta. [In fact, the recipe I’m making today could be adapted to resemble a gluten-free lasagna, if you were so inclined.]
Last week at the church I volunteer at we made a lentil stew with a topping of thinly sliced, crispy potatoes. I brought my mandolin to slice them, and while I was doing that I started to have a hankering for scalloped potatoes. But me being me, I needed to level things up a bit, and turn it into a whole meal, rather than just a side dish. So, if you simply want to make scalloped potatoes (with or without cheese, which is a whole other debate) you can omit the mushroom-onion-ham filling I put in mine.
A Potato Dish By Any Other Name…
Growing up, Scalloped Potatoes were a side dish our family usually served with ham. They weren’t an everyday thing, more so reserved for special occasions, and I don’t recall them having much, if any, cheese in them. I’m not even sure where the term “scalloped” came from since most of the older recipes in the French tradition were referred to as “potatoes gratin” or pommes de terre gratinées or even gratin dauphinois. The term “au gratin” is most often used to describe things that have a cheesy crust on top, like French Onion Soup (aka, Soupe à l’oignon gratiné.) The one thing all those potato dishes have in common is they start with thinly sliced potatoes and are baked in a béchamel (white sauce) or mornay (béchamel with cheese added) and end up with a crispy, browned layer of potatoes on top.
Scalloped Potatoes with Mushrooms, Onions, and Ham
As with all my no-recipe recipes, this dish can be modified to suit your preferences and dietary needs or restrictions. Make all the substitutions you want, EXCEPT for the potatoes, because that’s kinda the point!
Ingredients
The amounts given are for a 9”x13” (23cm x 33cm) baking dish. If yours is larger or smaller, adjust the amounts accordingly. This recipe will serve 6-8 people, depending on how hungry people are, and whether anything else is being served along side. [Apologies for the inconsistencies of weights and measures below as I didn’t actually weigh or measure anything.]
4 medium-sized Yukon Gold potatoes, thinly sliced
1 large or 2 medium-sized onions, peeled and thinly sliced
1 pint (225g) mushrooms, thinly sliced
2 cloves garlic, minced
Ham, cut into cubes (I didn’t weigh mine, but it was about 2 cups)
Olive oil
2-3 sprigs fresh thyme (optional)
Splash of Vermouth or white wine (optional)
Salt & pepper to taste
2 cups / 500mL whole milk (or if you want to be really decadent, use 18% cream)
2 Tbsp butter
2 Tbsp flour
2 teaspoons ground nutmeg (I grated half a nutmeg)
2 cups finely grated cheese (I used a blend of Gruyère, Emmental, mozzarella, and Parmesan because that’s what I had on hand)
Method
Cut each mushroom in half, then slice them thinly
Sliced mushrooms Cut the onion(s) in half, peel, then slice them thinly
Sliced onions Smash the two cloves of garlic, peel them, then finely mince.
Minced garlic Put all of this into a bowl and set aside.
Slice and chop up some ham (I didn’t use this whole ham, just the smaller, outside slices because I’m saving the bigger slices for something else.) About 1 1/2 cups.
Diced ham You can peel your potatoes or leave the skins on (I left them on because Yukon Gold have very thin skins and they add lots of vitamins and fiber to the dish.) Wash them well. If you use russet/baking potatoes, you’ll probably want to peel them.
Ushing a mandolin or very sharp knife*, slice the potatoes about 1/8” thick (3mm) and place them directly into a bowl of milk (I used the baking dish I’d be baking them in later.) Normally, we put sliced or cut potatoes in water to keep them from browning, but when you do that you lose a lot of the natural starch from the potatoes, so that’s why I put them in the milk I’ll be using for the sauce. That residual starch will help the milk thicken up while baking. I also covered them with plastic wrap to ensure no discolouration.
*If using a knife, cut a small slice on the flattest surface of the potato to give you a flat, stable surface for cutting. You don’t want your potato rolling around on you while trying to make thin slices.
Slicing the potatoes, then storing them in milk
Heat up a large skillet with 1-2 tablespoons of olive oil, then sauté the mushrooms, onions, and garlic until very soft and all their liquid has been released and evaporated. It’s important to cook off as much liquid as possible so that the finished dish isn’t too liquidy.
Sautéing the onions, mushrooms, and garlic in olive oil. Add Thyme if you have it. Once the vegetables are cooked, add the diced ham and continue to cook until the mixture starts to brown just a bit. Deglaze the pan with Vermouth or white wine, if desired, then remove the sprigs of thyme and transfer the mixture to a bowl.
Add the ham, continue cooking, then deglaze with Vermouth Mix 2 tablespoons of flour with 2 tablespoons of soft butter into a paste (this is called beurre manié) which will help the milk sauce thicken. Set it aside.
Beurre manié (a paste of equal parts butter and flour) Finely grate your cheese(s) until you have about 2 cups. I used mostly Emmental, but I also added a tiny bit of Gruyère I had left, along with some mozzarella and Parmesan. Use whatever you have/like (though I think this looks best with a white cheese as opposed to one that’s orange.)
Finely grated cheeses Start layering potatoes in the baking dish, adding some of the milk, a sprinkle of grated nutmeg, and a few dollops of the butter/flour paste.
Add the ham/vegetable mixture and half of the grated cheese.
Ham/onion/mushroom layer, then cheese Finish with a final layer of sliced potatoes, butter/flour, the rest of the milk, and the last of the cheese. Cover with plastic wrap and refrigerate until ready to bake.
A final layer of potatoes and grated cheese When ready to bake, preheat your oven to 375°F/ 177°C. Loosely cover the baking dish with foil (dull side out) making sure it’s not touching the cheese. If that’s unavoidable, lightly brush the shiny side of the foil with olive oil to help prevent it from sticking to the cheese as it melts. Place the baking dish on a baking sheet (to catch any spillovers) and place it on the upper-middle rack of the oven.
Bake for 60 minutes, or until the potatoes are soft and the liquid is bubbling. Remove the foil and return the baking dish to the oven for another 20 minutes, or until the top/edges of the potatoes and cheese on top have started to brown
The finished product, right out of the oven Let sit for about 15-20 minutes before slicing and serving so the potatoes have a chance to soak up some of the sauce and has a chance to thicken up.
Wrap any leftovers well, which will keep in the fridge for 5 days or so, or wrap individual portions and freeze for a couple of months.
Final Notes
The sauce for this ended up being a little thinner than I was expecting, likely because of the addition of the mushrooms, onions, and ham, which—even though I cooked them well—gave off even more liquid during baking. That might have been remedied by cooking the filling much longer to extract more liquid, but a runnier sauce just might be inevitable.
Another change you could make would be to make a mornay (i.e., cheese sauce) to pour over the potatoes and the filling, rather than just using the milk and beurre manié. To do this, make a roux by melting the butter in a small pot, then adding the flour and cooking it over medium heat for a couple of minutes. Add the milk and whisk constantly until the sauce thickens. Take it off the heat and add 1 cup of the shredded cheese, whisking to combine. Pour this over the layers of potatoes and ham filling, then top with the other 1 cup of cheese.
Despite the somewhat runny texture, this dish tasted amazing! I’m really looking forward to leftovers in the coming days.
Wine Pairing
This dish would go well with any white wine, especially one with high acidity to cut though the richness of the sauce and the cheese. An Alsatian (French) Riesling or Pinot Gris would go well with this, as would a rich Ontario or Burgundian Chardonnay that has undergone malolactic conversion to bring out the cheesy/buttery notes.
Willm Réserve Riesling, Alsace, France, $19.95
2023 Flat Rock Cellars, The Rusty Shed Chardonnay, VQA Ontario, $32.99
Looks incredible. Yummy!