Cheesy Scalloped Potatoes with Caramelized Onions

These Cheesy Scalloped Potatoes with Caramelized Onions are rich, decadent, and perfect for a holiday brunch or dinner. They are elevated with the addition of caramelized onions that add amazing flavor to compliment the cheesy potatoes.

This scalloped potatoes recipes out of this world! Layers of tender potatoes, golden caramelized onions, and a rich cheese sauce make the most indulgent dish. Don't forget the crispy breadcrumbs on top. This is such an indulgent dish that is perfect for brunch or even as a side with dinner! Scalloped potatoes are not a super quick recipe to make, but the time and effort is so worth it!

Ingredients for Caramelized Onion Cheesy Scalloped Potatoes:

The ingredients for this scalloped potatoes recipe are so simple! You can always swap in a different cheese as well. Here's what you need:

• Sweet, Yellow Onions - thinly slice the onions using a sharp knife or a mandoline. A mandoline makes the process super easy but be careful using it.
• Butter
• Russet Potatoes - peeled and thinly sliced (⅛ inch thick or thinner is key!)
• All-Purpose Flour
• Milk - I like to use whole milk for a rich cheese sauce, but you can also use 2% fat milk.
• Grated Gruyere Cheese - Or a Swiss/Gruyere Blend (like the one at Trader Joe's)
• Italian Seasoned Breadcrumbs
• Spices: Salt, Pepper, Dried Thyme

How to Make Scalloped Potatoes

If you're new to making scalloped potatoes from scratch, I break down the steps for you. My best tip is to use a mandoline for easy slicing! See the step by step below:

1. Caramelize Onions
2. Slice Potatoes: They should be ⅛ inch or even thinner. If the potato slices are too thick, then they will take way too long to cook. I recommend using a mandoline, carefully, to thinly and evenly slice the potatoes.
3. Make Cheese Sauce: Get the oven preheating and make the cheese sauce.
4. Assemble Scalloped Potatoes - Layer the potatoes, caramelized onions, cheese sauce, and shredded cheese in a greased baking dish.
5. Bake - Toward the end if the top is starting to get brown you can loosely tent with foil. Bake until the potatoes are fork tender.
6. Serve and Enjoy - Allow to cool for 10-15 minutes before cutting and serving. Allowing it to cool slightly helps the slices hold their shape.

How do you make caramelized onions?

Traditionally, caramelized onions are made on the stove. The process takes about an hour and requires occasional stirring. If you don't want as much hands on time, you can also make caramelized onions in the slow cooker! Here's the easy recipe for slow cooker caramelized onions. You can make a batch and I love making use some of them in this recipe.

What kind of onions do you use for caramelized onions?

You can use any onion you're like for caramelized onions - yellow, red, white, or sweet yellow. I prefer using sweet yellow onions for the added sweetness. If you use another variety of onion, you can add a spoonful of sugar if you'd like.

Leftovers and Storage

Although cheesy scalloped potatoes are best served soon after making - due to the cheese sauce - leftovers can be stored in the fridge for up to 5 days. Either transfer to an airtight container or tightly wrap the top with plastic wrap. Make sure it fully cools to room temperature before transferring to fridge.

Recipe Notes and Tips:

• A Mandoline is your Best Friend - While you can thinly slice onions and potatoes with a sharp knife, it is so much easier to use a mandoline slicer.
• Soak Potato Slices in Water - After you slice your potatoes, keep the slices in a big bowl of ice water. This keeps the potatoes from turning brown while you're waiting to assemble and bake.
• Caramelize Onions in Advance - To cut down on day of prep time, caramelize your onions in advance! You can do it on the stove top up to 5 days in advance or make a batch in your slow cooker up to 5 days in advance as well.

Other Recipes Using Caramelized Onions:

• Caramelized Onion and Pancetta Quiche - Skip the onion step in the recipe and just use about ¾ cup of caramelized onions for the filling.
• Caramelized Onion Dip - Mix the onions sour cream, mayo, spices, and chives to make a yummy, creamy dip for chips.
• BBQ Chicken Sliders - Instead of the sliced, raw red onions use caramelized onions on top of the bbq chicken.

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