Crockpot Potatoes Au Gratin

VERY generously spray your slow cooker with nonstick spray. I used a 6-quart slow cooker for the recipe. Note that smaller crockpots may not be able to cook through all the potatoes evenly so you will have to halve (or cut in thirds) this recipe.Wash and peel the potatoes. Cut into medium thick slices (see picture for general width). Measure the potatoes -- you should have about 5 cups total.Place a layer of potatoes at the bottom of the crockpot. Generously (or to your preference, but don't skimp on the salt or it will be more bland) sprinkle on seasoned salt and pepper. Layer another layer of potatoes and sprinkle on salt and pepper. Repeat this process until all the potatoes are layered in the crockpot.In a medium-sized pot over medium heat, add in the butter. Melt completely and then vigorously whisk in the flour until a thick dough forms. Whisk constantly for 1 minute. Add in the garlic and onion powder and continue to whisk.Very slowly add in the milk whisking as you add it. In between milk additions whisk the mixture and allow it to thicken.Once all the milk is added in and the mixture is completely smooth and thick, add in the sour cream. Whisk to add. Add in the freshly grated cheddar cheese and whisk until completely melted and the mixture is smooth.Add some more salt and pepper here if desired.Pour this cheese sauce evenly over the potatoes. Shake the slow cooker to get the creamy cheese sauce evenly throughout the crockpot. Do not stir it in.Place 3 paper towels on top of the crockpot (this will absorb lots of moisture and keep the potatoes crispier) and then place on the lid.Place on high (my experimentation with low heats were unsuccessful.) for 3-5 hours depending on the heat of your slow cooker. Slow cookers cook at different temperatures and speeds! Mine took just under 3 hours -- check frequently to avoid burning the edges or over cooking the potatoes so they are mushy.Halfway through the cooking time, change out the paper towels for fresh ones.Once the potatoes are tender and cooked through, remove the lid and garnish with fresh parsley or chives and additional seasoned salt and pepper. Allow to cook without the lid for 15-20 minutes to get a bit crisper on top if desired.This recipe is for classic au gratin potatoes -- feel free to add more toppings or seasonings as you enjoy your au gratin potatoes. Some ideas are to chop up an onion and add that in (I would sauté it in olive oil first), add some red pepper flakes for heat, some cooked and chopped bacon, paprika, more or different flavors of cheeses...