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.
- 4 large sweet, yellow onions, cut in half then thinly sliced
- 1/4 cup unsalted butter
- 1 teaspoon dried thyme
- Pinch of salt and pepper
Cheesy Scalloped Potatoes
- 3 pounds russet potatoes
- 1/4 cup unsalted butter
- 1/4 cup all-purpose flour
- 3 1/2 cups whole or 2% milk
- 1/2 teaspoon dried thyme
- 16oz shredded gruyere cheese or swiss/gruyere blend
- 1/4 cup Italian breadcrumbs
- Salt and Pepper
- Caramelize Onions: Melt the butter in a large skillet over medium heat then add the sliced onions. Cook on medium for 10 minutes, stirring occasionally. Reduce the heat to medium-low and cook for another 30-40 minutes until the onions are golden brown and caramelized. Stir the onions occasionally while cooking – if they are starting to stick to the pan, you can add a splash of water. Adjust the heat as necessary depending on your stove top. Once done, stir in the salt, pepper, and thyme.
- Slice Potatoes: While the onions are cooking, peel and thinly slice the potatoes. They should be 1/8 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. Add the potato slices to a large bowl of ice water to keep them from getting brown.
- Make Cheese Sauce: Get the oven preheating to 375 degrees F and make the cheese sauce. Start by melting the butter in a pot over medium and slowly whisking in the flour – to make a roux. Cook and stir until the roux is golden in color. Slowly whisk in the milk until smooth. Bring to a gentle simmer then stir in about half of the cheese, the thyme, and a pinch of salt and pepper. Stir to combine and melt the cheese. The sauce should be smooth and thick enough to coat the back of a spoon – you can let it simmer for a few minutes to thicken. Remove pot from heat.
- Assemble Scalloped Potatoes – Well grease a 9×13 inch baking dish with cooking spray. Layer half of the potatoes to the bottom of the baking dish – it’s best to lay each potato slice individually vs adding stacks that will take too long to cook. Pour half of the cheese sauce over the potato slices then sprinkle over about half of the caramelized onions and half of the remaining shredded cheese. Top with the remaining potato slices and pour over the rest of the cheese sauce. Finish by adding the rest of the onions, the remaining cheese, and sprinkle the breadcrumbs on top.
- Bake – Bake the cheesy scalloped potatoes uncovered for 50 – 60 minutes. Toward the end if the top is starting to get brown you can loosely tent with foil. Bake until the potatoes are fork tender.
- 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.
- Prep Time: 1 hour
- Cook Time: 1 hour
- Category: Side
- Method: Oven
- Cuisine: American
Keywords: Cheesy Scalloped Potatoes, Scalloped Potatoes Recipe, Scalloped Potatoes with Onion, Caramelized Onion Scalloped Potatoes