I do not use my mandoline slicer enough. That thing is so damn cool, making those perfect little slices. Since I bought a huge bag of russet potatoes on sale last week, I figured it was an ideal situation for scalloped potatoes.
I more or less followed this recipe on allrecipes.com for Creamy Au Gratin Potatoes. I bumped up the serving size to 6, because I wanted to use up more of my potatoes, but that was dangerous because I had enough sliced potatoes to get right up to the edge of my baking dish.
For simplicity's sake, here's the ingredient list along with my inevitable tweaks. This will make enough for either an 8x8 dish or a deep pie plate, which is what I used. Technically 6 servings, but it's so delicious you're realistically looking at 4.
Cheesy Scalloped Potatoes
6 russet potatoes, sliced into 1/4 inch slices
1 large onion, sliced thin
1 tsp thyme
Salt and pepper
2 cloves of garlic
3 tablespoons butter
3 tablespoons all-purpose flour
2 cups milk plus a little more
1 cup shredded Cheddar cheese
Bacon salt (just a smidge)
I used less milk and less cheese than the recipe calls for, and I added thyme, garlic, and bacon salt. I would have added actual bacon bits but I didn't have any bacon in the house (a problem which will be corrected on my next grocery run). The recipe, as written on the allrecipes site, seemed a little bland without any seasoning, so I figured I couldn't go wrong with garlic and thyme. The recipe also had me putting the raw onions between potato layers, but I figured cooking them first would have a better result.
Soften the onions and thyme in a small pat of butter on medium heat and set them aside. Peel two garlic cloves and smash them flat with a knife so all their guts are hanging out but they're still more or less holding together. Melt the butter over low heat and whisk in the flour to get a nice silky sludge - cook that for a minute or so until it changes to a golden color, then stir in 2 cups of milk and your garlic cloves, and cook, whisking like mad, for a few minutes until it thickens up. Take it off the heat, add salt and pepper, fish out the garlic cloves with a slotted spoon, and then stir in the grated cheese.
Set the oven for 400.
Peel, then slice the potatoes with a mandoline slicer, or with a knife if you're a masochist. Generously grease the bottom of your baking dish with butter or a cooking spray, and layer some potatoes in. Add some of the onions on top, then a little sauce, then more potatoes. Keep going until you're at the top of the dish, then pour as much of the remaining sauce over the top as you can without making a mess. Press down on the gooey mess with your hands to force the sauce between the layers. If you've been adding sauce as you layer, you may not need to do this part.
If your sauce has thickened up too much while you were peeling and slicing your potatoes, just whisk in a little extra milk.
Sprinkle a little bit of bacon salt over the top layer and then add a small handful of grated cheese, then put the baking dish on a cookie sheet to catch bubble-overs. Put that into your oven for about an hour - pull it out after that long and check it with a sharp knife. If you have to force the knife through, put them back in for a while. If the knife goes through the potatoes with only a tiny bit of resistance, they're done.
Let everything sit and cool off a little once the potatoes are cooked, because that will let the sauce thicken up a so the potatoes hold together better when you scoop them on to a plate.
I just now realized this is very similar to the "Cheesy Garlic Scalloped Potatoes" I posted about last year, but I already took all this time to write it out, so it stays. For some reason, the Blogger search doesn't always pull everything up, so when I searched for "potatoes" to see if this was a repeat, it didn't turn up. I only caught it because I decided to edit my old posts to add a "potatoes" tag. Oh well. At least my spices were different this time, and the cooking time and temperature were different because I used a smaller dish, making a taller stack of potatoes. Does that make it different enough to count as a new post?