Homemade au gratin potatoes are baked up warm and hearty in a rich sharp cheddar cheese sauce and brightened with fresh thyme. It’s a true treat you can make ahead and bake when you’re ready–just try to let them cool!
Sometimes I think the words I use to describe this blog aren’t fair. I use words like easy. What I should say, is doable. Realistic or logical.
That’s who I am as a person–and I’m never going to ask you to master the French baguette or make puff pastry. I want you to have recipes that are awesome to eat and easy enough that (as long as you follow the directions) you can make even if you aren’t totally kitchen confident.
This blog is full of food like that and for some reason side dishes like these homemade au gratin potatoes are always a favorite. If you’ve ever tried my baked mac and cheese that everyone loves, then you’ll be in luck with this recipe because I used the same basic sauce (changed the cheese, added a few things) and transformed regular potatoes in to something you won’t want to get your hands out of.
How to make the best homemade au gratin potatoes
There are so many ways you can go with this recipe but if you want to try it my way first, do that. Then add your own favorites. Here’s what I will tell you:
- When you add the milk to the butter and flour, do not walk away from that pan. Just don’t. Stand there and stir. Not like a wild person, but just gently stir. If you don’t, your sauce will split and you’ll tell me it was sandy and I have no idea what a sandy sauce even is. (I speak from experience.)
- Use a sharp, aged white cheddar cheese here. You can find that in most stores, and it’s a bit harder than a regular cheddar. It will be in a special area and not in with the shredded cheeses. You’ll have to grate your own.
- Use fresh thyme here or use half as much if you are using dried. I just hate most dried herbs. I always say they are like the difference between a raisin and a grape. They used to be the same thing but now they’re–not.
To make these homemade au gratin potatoes ahead: layer them in your baking dish with the sauce and allow it cool to room temperature. Cover with plastic wrap and chill for up to two days. Allow the dish to come warm a bit on the counter (about 30 minutes or so) before baking. Cover them halfway through if they are getting too dark on top. (Also speaking from experience.)
Homemade potatoes au gratin baked up warm and hearty in a rich sharp cheddar cheese sauce and brightened with fresh thyme. It's a true treat you can make ahead and bake when you're ready.
- 2 pounds russet potatoes, peeled and sliced very thinly (less than 1/4" thick) a food processor with a slicing blade is good for this
- 5 tablespoons butter or margarine
- 1/3 cup all purpose flour
- 3 cups milk (whole, 2% or skim)
- 1 1/2 teaspoons salt
- 1/2 teaspoon black pepper
- 3 cups shredded aged white cheddar cheese
- 1/2 teaspoon onion powder
- 1/2 teaspoon garlic powder
- 2 teaspoons fresh thyme leaves or 1 teaspoon dried thyme
If baking right away, preheat the oven to 400. Lightly grease an 11x8x2" (or slightly larger) baking dish with cooking spray and set aside.
In a large skillet over medium heat, melt the butter and add the flour, stirring constantly 1-2 minutes until the flour and butter starts to get a little bit brown.
Add the milk and stir constantly until the sauce begins to thicken and comes to a low bubble--about 8 minutes. Add the salt and pepper.
Turn off the heat and add in the cheese, a few handfuls at a time, stirring until they melt in. Add the onion powder, garlic powder, and thyme leaves in and stir.
Add a layer of potatoes to the bottom of your dish, and pour over 1/3 of the sauce.
Continue to layer until you reach the top of your dish and end with the sauce.
Bake uncovered 30-45 minutes, then cover with foil and bake an additional 45 minutes or for a total of 1 1/2 hours. Serve warm.
Bake this on a foil lined cookie sheet to catch any spills!