Southwest Au Gratin Potatoes with Cheddar and Jalapeño

I’m excited to share my favorite recipe for Southwest Au Gratin Potatoes — a creamy, cheesy casserole with a bright Southwestern kick from green chiles and spices.

These potatoes are rich and comforting yet lively thanks to cumin, paprika and a touch of chili powder. Thin, even slices give the best texture, so if you have a mandoline use it; a sharp knife will work as well. Letting the casserole rest a few minutes after baking helps the sauce set and the flavors meld.

How to Make Southwest Au Gratin Potatoes

Ingredients List

• 2 lbs Yukon Gold or russet potatoes
• 2 tbsp kosher salt (divided)
• 2–3 green chiles (canned or roasted, to taste)
• 3 garlic cloves, minced
• 2–2 1/4 cups heavy whipping cream
• Cooking spray or a little butter for the dish
• 2–3 tablespoons all-purpose flour (see notes)

Southwestern seasonings (suggested):

• 1/2 teaspoon hot chili powder
• 1/4 teaspoon ground cumin
• 1/4–1/2 teaspoon smoked paprika (optional)
• 2 cups shredded cheese (smoked cheddar, pepper jack, or a blend)

Step-by-step process

Step 1 — Preheat

Preheat your oven to 350°F (180°C). Grease a baking dish with cooking spray or butter.

Step 2 — Slice and season the potatoes

Slice potatoes about 1/8-inch (3 mm) thick using a mandoline or a sharp knife. For Yukon Gold use 4–6 medium potatoes; for russets, 3–4 large potatoes.

Place slices in a large bowl and toss with 1 teaspoon of the salt and the southwestern seasonings, coating evenly.

Step 3 — Make the cheese sauce

Mince garlic and set aside. In a medium saucepan, melt 3 tablespoons butter over medium heat. Stir in the flour and cook 1–2 minutes until smooth and slightly bubbly.

Slowly whisk in the heavy cream and bring to a gentle boil, stirring constantly. Cook 2–3 minutes until the sauce thickens. Remove from heat and stir in the minced garlic and 2 cups shredded cheese until melted and smooth.

Step 4 — Add the chiles

Finely chop 2–3 green chiles depending on heat preference and stir them into the cheese sauce until evenly distributed.

Step 5 — Assemble the casserole

Spoon a thin layer of cheese sauce into the bottom of the prepared baking dish. Arrange a single layer of potato slices over the sauce, then cover with more sauce. Continue layering potatoes and sauce until all are used, finishing with a final layer of sauce. Sprinkle extra cheese on top if desired.

Step 6 — Bake

Bake 60–75 minutes, or until the potatoes are tender and the top is bubbly and golden. Let the casserole rest about 10 minutes before serving so it sets and slices cleanly.

Enjoy the creamy, cheesy flavors with a Southwestern twist.

Side Dishes for Southwest Au Gratin Potatoes

Southwest Au Gratin Potatoes are rich and flavorful, making them an ideal side for holiday meals or hearty weeknight dinners. Pair them with:

• Roasted beef or pork — the savory meat balances the cheesy potatoes and makes for a satisfying main course.
• Green beans almondine — bright, lightly sautéed green beans with toasted almonds and lemon zest cut through the richness and add a fresh contrast.
• A simple green salad or steamed vegetables for a lighter accompaniment.

Ingredient Substitutes

If you need to swap ingredients, here are reliable alternatives:

Waxy potatoes

Red or fingerling potatoes can be used instead of Yukon Gold. They hold their shape well during baking and provide a firmer texture.

Pepper Jack

Pepper Jack adds a spicy kick that enhances the Southwestern character. Use it on its own or mixed with a milder cheese.

Cheddar cheese

Medium cheddar is a good choice if you prefer a milder, creamier flavor than sharp cheddar. A blend of smoked cheddar and a melting cheese gives great depth.

How to Store Southwest Au Gratin Potatoes

Proper storage keeps the dish tasting its best:

Refrigerate

• Cool to room temperature before storing to avoid condensation.
• Transfer to an airtight container and refrigerate at 35–40°F (2–4°C).
• Stored properly, the casserole will keep for 3–4 days.

Freeze

• For longer storage, cool completely, then place in a freezer-safe airtight container or wrap tightly in aluminum foil and label with the date.
• Freeze for up to 2–3 months. Reheat gently in the oven to restore texture and flavor.
• Always check for signs of spoilage before reheating and serving.

Common Mistakes to Avoid

Keep these tips in mind for a successful dish:

• Don’t omit green chiles — they provide the signature Southwestern flavor.
• Avoid overbaking or underbaking — bake until the potatoes are fork-tender and the top is golden and bubbly.
• Season carefully — use seasoned or kosher salt and taste the sauce before baking to ensure balanced seasoning.
• Grate your cheese from a block when possible — pre-shredded cheese can contain anti-caking agents that affect melting.