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Southwestern Au Gratin Potatoes

Southwestern Au Gratin Potatoes

Southwestern Au Gratin Potatoes. I saw these on a menu recently when I was looking for takeout. I didn’t order them so I don’t know how this recipe compares but I did copy down the description:

Idaho and Yukon gold potatoes in a creamy jalapeno spiked sauce topped with pepper jack and smoked cheddar cheeses.

‘I can do that myself‘ is a thought that I have often – so often that perusing restaurant menus is one of my favorite ways to get inspiration. I took this and ran with it, and we loved the results. Now it’s your turn!

Southwestern Au Gratin Potatoes Ingredients

Southwestern Au Gratin Potatoes Ingredients

Feel free to jump to the full recipe, but here are useful notes about the ingredients you will need to make this Southwestern Au Gratin Potatoes recipe:

  • Yellow potatoes: These waxy potatoes hold their shape well and release enough water to loosen the sauce just enough while it cooks so it soaks in and coats each slice beautifully. Use a mandoline or your sharpest knife and keenest eye to slice them thinly. Please note that if you substitute russet potatoes you will need either fewer potatoes or more heavy cream. If this sounds complicated, stick with the recipe as written or find a different one.
  • Yellow onion: Slice them paper-thin, just like the potatoes. We’re after their flavor and not much else. By the time the potatoes come out of the oven, these will have reduced to almost nothing.
  • Jalapeno: We slice these as thinly as the onion and the potatoes, seeds and all. Those are where most of the kick in these Southwestern Au Gratin Potatoes comes from.
  • Garlic: Our favorite warm and friendly aromatic.
  • Heavy cream: The base of our sauce. It blends with the water released from the potatoes and gives everything the perfect consistency. Using an alternative liquid will change the final results, so don’t – or at least keep that in mind.
  • Smoked pepper jack: Pepper jack, but with another dimension. I can find it at my local Wegmans, and it can be ordered online as well. Sometimes it can be easier to find smoked cheddar than smoked pepper jack, so feel free to use smoked cheddar if you can’t find smoked pepper jack. Using smoked variations of both would be a bit much, I think.
  • Medium cheddar cheese: Sharp or extra sharp is my preferred cheddar, but medium gives it a tang without overpowering the smoke. Again, if you use smoked cheddar, go for regular pepper jack.
  • All-purpose flour: Just a bit, to help thicken the sauce.
  • Unsalted butter: Any fat will work: oil, ghee, margarine, whatever you want to use.
  • Hot chili powder, paprika, ground cumin, Mexican oregano, cayenne pepper: If you know me and mine you already knew that jalapeno wasn’t going to be enough, so we’ve got cayenne and hot chili powder to give it a boost. The other flavors are to round things out because they’re Southwestern Au Grain potatoes, not just Spicy Au Gratin Potatoes!
  • Seasoned salt: Kosher salt will work just fine.
  • Equipment: I like to make these in glass baking dishes, but a few different vessels will work:
Southwestern Au Gratin Potatoes

How to Make Southwestern Au Gratin Potatoes

Full instructions are included in the recipe below, but here is a basic overview of what you’ll need to do, along with some important tidbits to help you make the most of this Southwestern Au Gratin Potatoes recipe:

  • Get everything ready! Preheat the oven to 425°F and make sure one rack is in the center of the oven. Grab a 9×13 baking dish and oil it up. I like to just spray it with cooking spray, but you can grease it with oil or shortening. Set it aside. Make sure you’ve combined your cheeses together in a bowl. Set that aside too.
  • Cook the aromatics. Melt the butter in a saucepan over medium heat, then add the onion and jalapeno slices. Cook for about 7 minutes, stirring occasionally until they’re all softened and pliable.
  • Build the sauce. Stir in the flour. Coat the onions and jalapenos in it, and let it cook for 2 minutes more. Add the garlic cloves and cook for another couple of minutes. Very slowly add the heavy cream. Next, add all of the seasonings – except the cayenne.
  • Cheese it up! Add in about 2/3 of the shredded cheese blend. The rest will go on top. Once the cheese has completely melted into the sauce, remove it from heat. Taste it for seasonings and adjust as you like. 
  • Layer your taters. Stack the ingredients for these Southwestern Au Gratin Potatoes like you’re building a lasagna. Spread some sauce out on the bottom of the pan, then add a layer of potatoes. Repeat more sauce, more potatoes, until it’s all gone! The sauce should be the top layer, over which you’ll sprinkle on the remaining cheese.
  • Bake. Cover tightly with aluminum foil and bake for 25 minutes on the middle rack. You might want to spray the underside of the foil with nonstick spray so it doesn’t take any of the cheese with it when you remove the foil after those 25 minutes. Return it to the oven uncovered for another 25-30 minutes, until browned and bubbling. 
  • Serve. Let rest at room temperature for at least 15-20 minutes before serving. No, it won’t get cold. I like my food BURNING hot, like a level that is uncomfortable for most people, so I would not steer you wrong. It will barely cool off tbh, but letting it rest will give the sauce time to congeal so it’s very necessary. Unless you enjoy liquid running all over your plate. 🤷🏽‍♀️
Southwestern Au Gratin Potatoes

Customize these Southwestern Au Gratin Potatoes

Into Tex-Mex but not good with spicy stuff? Interested in swapping the cheeses but not sure what to use? Check out some suggestions for how you can make this Southwestern Au Gratin Potatoes recipe perfect for your taste:

  • Mild Southwestern Au Gratin Potatoes – Remove the seeds and ribbing from the jalapeno before slicing it up. Omit the cayenne and swap the hot chili powder for regular chili powder. I’d use colby jack instead of pepper jack.
  • Three-Cheese Au Gratin Potatoes – Swap the smoked pepper jack for smoked gouda, and the medium cheddar for sharp white cheddar. Sprinkle grated parmesan over the top instead of cayenne pepper. This would be very similar to the Three-Cheese Scalloped Potatoes recipe in my digital cookbook As Seen On IG.
  • Southwestern Bacon Au Gratin Potatoes – It’s just what it sounds like! Fry up some bacon (beef bacon if you’re me), chop it into large pieces, and stir it in the sauce after you remove it from heat (step 5 in the recipe). Now you’ve got a one-dish meal, perfect for those folks that can’t consider a meal complete without some sort of meat if you don’t feel like making a main.

Let me know what you think of this recipe if you try it! Looking for another Tex-Mex meal idea? Check out my Southwestern Chicken Stew if you haven’t already. Here’s a Pinterest graphic:

Southwestern Au Gratin Potatoes
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Southwestern Au Gratin Potatoes

Southwestern Au Gratin Potatoes

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  • Author: María
  • Total Time: 1 hour 20 minutes
  • Yield: 10 1x


Creamy, spicy, cheesy, deliciousness.


Units Scale
  • 2 lbs yellow potatoes, thinly sliced
  • 1 small yellow onion, thinly sliced
  • 1 medium jalapeno, thinly sliced
  • 3 garlic cloves, minced
  • 2 1/4 C heavy cream
  • 2 C smoked pepper jack
  • 2 C medium cheddar cheese
  • 2 tbsp all-purpose flour
  • 2 tbsp unsalted butter
  • 1/2 tsp hot chili powder
  • 1/4 tsp ground cumin
  • 1/4 tsp dried Mexican oregano
  • 1/4 tsp seasoned salt, to taste
  • 1/8 tsp cayenne pepper, optional


  1. Preheat the oven to 425°F and spray a 9×13 baking dish with cooking spray. Set it aside. Add the cheeses to a medium-sized bowl and combine them together with a fork. Set that aside, too. 
  2. In a medium saucepan over medium heat, melt the butter. Once melted add the sliced onion and jalapeno. Toss in the butter and cook, stirring occasionally until softened and pliable.
  3. Next, sprinkle the flour over the onions and jalapenos. Stir to coat them in the flour and let them cook for 2-3 minutes, then add the minced garlic. Cook for 2 minutes more. 
  4. Pour in the heavy cream, either gradually or in batches to avoid lumps. Once completely incorporated stir in all of the seasonings except the cayenne pepper followed by 2/3 of the cheese. 
  5. Once the cheese has completely melted into the sauce, remove it from heat. Taste it for seasonings and adjust as you like. 
  6. Spoon a small amount of sauce into the bottom of the prepared baking dish and smooth it around with the back of the spoon. Cover it completely with 1/3 of the sliced potatoes, as evenly as you can. Ladle more sauce over the potatoes in thin ribbons, smooth that out and repeat the potato layer with another 1/3. Repeat these steps one more time and top it with all of the remaining sauce. 
  7. Spread the remaining cheese across the top evenly, as best you can. It’s OK if there are a few bare spots, it’ll make for a delicious texture. Sprinkle to cayenne pepper over the top.
  8. Cover tightly with aluminum foil and place in the oven on the middle rack for 25 minutes, then remove the foil and return to the oven for another 25-30 minutes until browned and bubbling. 
  9. Let rest at room temperature for at least 15 minutes before serving. It will barely cool, but it will give it time to congeal a bit so it doesn’t run all over the place when you’re attempting to serve it. 


There are tips for success in the post above the recipe. 

  • Prep Time: 30
  • Cook Time: 50
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