I make this when I'm craving comfort food. Something creamy, something cheesy, something with potatoes. Sometimes I just want a big mess of ooey gooey creamy cheesy artery-clogging potatoes, and I think this recipe I accomplishes that! Mind you I don’t splurge on eating this much cheese and dairy that often all at once, but sometimes you just have to throw caution to the wind and indulge. —anotherfoodieblogger
Preheat oven to 375 degrees. Boil the whole, peeled potatoes for about 15 minutes — just long enough to slice through easily but you don’t want them mushy.
Meanwhile saute one tablespoon of the butter, chopped onion, and garlic in a small skillet until softened.
When the potatoes are done, drain and wash under cold water until cool enough to handle.
Spray a 2-quart casserole dish with oil. Slice the potatoes thinly and layer in the dish and set aside.
In a medium saucepan, melt the remaining butter over medium heat. Stir in the flour and combine to make a paste. Then add the milk all at once and whisk until it starts to thicken. Add the cayenne pepper, then season to taste with Mrs. Dash (or salt) and black pepper. Then add the onions and garlic, and then the sour cream. Lastly, add the cheddar and Parmesan cheeses. Stir well until all combined, then pour over the the potatoes.
Pop that baby in the oven for about 45 minutes until bubbly. Carefully sprinkle some additional cheddar and Parmesan cheese on top, then broil for about 5 minutes until the top cheese is nice and brown. Remove from oven and let sit about 10 minutes, if you can wait that long!