1cupsharp cheddar cheesegrated, plus more for topping
salt and pepperto taste
let's do it
Preheat the oven to 350 degrees and spray an 8" square casserole dish with cooking spray.
Rinse and peel each potato and place in a bowl of cold water as you slice it—this will prevent the potato from oxidizing and turning brown. Slice all of the potatoes about ⅛" to ¼" thick.
Next, slice the onion as thinly as possible then place it, along with the sliced potatoes in a pot of salted water. Bring to a boil over high heat then immediately reduce the heat to medium-low and simmer gently until the potatoes are cooked through but still firm.
While the potatoes and onions are simmering, melt the butter in a large skillet over medium heat then add the flour. Whisk until the flour has dissolved into the butter and cook for about 2 minutes, stirring constantly. Add chicken broth, whisk until smooth, then stir in milk, garlic powder, salt and pepper. Bring the mixture to a bubble, reduce heat to medium-low and simmer 5-6 minutes until the mixture has thickened. NOTE: We strongly recommend you weigh your einkorn flour, if possible, for better accuracy. If you don’t have a scale, fluff the flour with a fork before you measure it in a cup.
Remove the skillet from heat, stir in shredded cheese and sour cream then transfer to a large bowl and set aside.
Drain the potatoes and onions into a colander then add them to the cheese mixture and gently stir to combine. Continue mixing gently until each potato slice is coated in the sauce. Taste the mixture and season to taste with salt and pepper. Transfer everything to the prepared casserole dish. Bake uncovered for 15 minutes, add some additional shredded cheddar cheese on top and continue to cook for another 10-15 minutes.
Remove the casserole from the oven and allow the dish to rest for approximately 10 minutes before serving. Enjoy!
One Last Thing
If you want to make this dish into a main meal, try adding cooked ham or chicken.