If you’re looking for a delicious and flavourful side dish then this Potatoes au Gratin with Caramelized Onions and Roasted Garlic is it! Perfect for holidays or anytime you need a delicious side!
Is there anything better than a potato-based side dish? Usually for the holidays, I keep it simple with mashed potatoes or baked potatoes but this time around, I felt like changing things up with this potatoes au gratin.
Why You’ll Love This Side Dish
- It’s a satisfying dish. I won’t lie to you, this is a heavy side since there’s potatoes, cheese, and a béchamel sauce but boy is it delicious.
- It’s not the prettiest side dish but it’s a super tasty! I won’t say it’s an easy recipe per say as it’s a little time intensive, but it’s tasty enough that it’s worth the effort. This dish is adapted from Craving Home Cooked. It’s already a tasty dish to start but I add caramelized onions, roasted garlic, and infuse herb flavours into the béchamel sauce which require an extra hour of work. Luckily, you can caramelize the onions while the garlic is in the oven.
- Components can be made ahead of time. Yes, I just said it takes an extra hour than your traditional potatoes au gratin but caramelized onions and roasted garlic can be made ahead of time so you break up the overall prep work.
Ingredients You’ll Need
- caramelized onion — to make caramelized onions, you’ll need 5 small onions, butter, and olive oil. You can see step by step photos in my how to make caramelized onion post.
- roasted garlic — to make roasted garlic, you’ll need two heads of garlic as well as olive oil and a pinch of salt. You can see step by step photos in my how to roast garlic post. You can also roast garlic in an air fryer.
- butter — unsalted butter is ideal as we are already adding salt to the béchamel sauce.
- all-purpose flour — you’ll need flour to make the roux for the béchamel sauce.
- chicken broth — I use low sodium chicken broth whenever possible.
- milk — I use whole milk.
- fresh herbs — I use rosemary and thyme.
- salt and pepper — you can swap the pepper for white pepper if you want it to blend into the béchamel sauce.
- Yukon gold — you can use Russet potatoes as well.
- cheese — I use both cheddar and mozzarella sauce.
- fresh thyme for garnish if desired
- cooking spray
How to Make Potatoes au Gratin with Caramelized Onions and Roasted Garlic
Make the Roasted Garlic
- Heat the oven to 400F.
- Remove the paper-thin skin of the garlic. Trim the top ¼ inch off the top of the garlic bulb.
- Place the heads of garlic onto a piece of tin foil and drizzle with olive oil, and sprinkle with salt. Tightly wrap the garlic in the foil.
- Roast in the oven for 40 to 60 minutes. When cool to touch, remove the garlic cloves from the skin and set aside. You can squeeze the cloves out or simply peel the skin off. Set aside for later.
Make the Caramelized Onions
- Add the onions and sauté for 5 minutes or until the onions have softened.
- Add the salt, if using, and reduce the heat to medium low and cook for 50 to 60 minutes. Stir the onions with a wooden spoon or spatula every few minutes, or until the onions are golden brown, and caramelized.
- Set aside for later. Before adding to the baking dish, pat the onions with some paper towels to absorb any extra moisture.
Make the Potatoes au Gratin
- In a small pot on medium low heat, melt the butter before adding the flour, bit by bit, and stir until evenly combined. Cook for a minute.
- Slowly pour in the chicken broth and whisk until combined.
- Slowly add in the milk, and whisk until combined.
- Add the salt, pepper, and fresh herbs and allow fresh herbs to infuse for 2-3 minutes on low heat, stirring constantly. Do not let it come to a boil. Remove from heat and remove fresh herbs before setting aside.
- Spray a 9×9 or 9×13 baking dish with non-stick spray.
- Spread half of the sliced potatoes in an even layer on the bottom of the pan and top evenly with the caramelized onions, roasted garlic, and half of the béchamel sauce.
- Top with half of the cheese.
- Layer the rest of the sliced potatoes on top before adding the rest of the béchamel sauce and cheese.
- Cover with tin foil and bake for bake for 45 minutes. Remove the tinfoil and bake for another 30 minutes, or until the potatoes are cooked through.
- Let rest for 15 minutes before slicing and serving. Top with some fresh thyme if desired.
Recipe Tips and Notes
- I use a 9×9-inch baking dish but it goes right up to the top. If you don’t want to risk overflow, use a 9×13-inch baking dish.
- I use a mandolin slicer to slice my potatoes evenly.
- I always buy extra potatoes as I don’t run the entire potato through the mandolin slicers as I prefer using the larger slices of the middle portion of the potatoes (and protecting my fingers lol).
- Resting before slicing gives the cheese time to set so the potatoes don’t fall apart as you serve them.
- You can mash the roasted garlic into a paste and mix it into the béchamel sauce. I just like having little surprise bits of cloves when I take a bite out of the potatoes au gratin.
- I highly recommend grating your own cheese instead of using a bag of pre-shredded cheese. The cheese melts much better as there isn’t an anti-clumping coating on cheese you shred from a block yourself. It’s super easy if you have a food processor as you can use the shredder blade and just run the block of cheese through it.
Make Ahead Tips
- Make ahead: make the roasted garlic and caramelized onion up to 3 days ahead of time. Store it in an airtight container in the fridge.
- Freezer: the potatoes’ texture may not be the same after freezing. If you’re ok with that, this potatoes au gratin can be frozen for up to 1 month after its been baked.
Potatoes au gratin or au gratin potatoes means “covered with bread crumbs or grated cheese and browned” according to Merriam-Webster.
For thin-skinned potatoes like Yukon Gold, I don’t peel the potatoes. Simply give them a good scrub and pat them dry before slicing. If you use russet potatoes, peel them before slicing as the skin is much thicker.
You can use any type of melty cheese such as gruyère, parmesan, smoky gouda, or spicy cheese for a kick of heat.
According to Southern Living, potatoes au gratin are more decadent as they are made with lots of cheese in between the layers of potatoes and on top as well.
Serving Ideas
Here are a few dishes that go well with potatoes au gratin:
Potatoes au Gratin with Caramelized Onions and Roasted Garlic
If you’re looking for a delicious and flavourful side dish then this Potatoes au Gratin with Caramelized Onions and Roasted Garlic is it! Perfect for holidays or anytime you need a delicious side!
Servings: 8 servings
Ingredients
For the Caramelized Onions
For the Potatoes au Gratin
- 3 tbsp butter unsalted
- ¼ cup all-purpose flour
- 1 cup chicken broth, low sodium
- 2 cups milk
- 1 tsp salt
- ¼ tsp pepper
- 5 sprigs fresh thyme
- 5 sprigs fresh rosemary
- 3 lbs Yukon gold, sliced into ⅛ inch rounds
- 1½ cup sharp cheddar cheese, freshly shredded
- 1 cup mozzarella, freshly shredded
- cooking spray
Instructions
For the Roasted Garlic
-
Heat the oven to 400F.
-
Remove the paper-thin skin of the garlic.
-
Trim the top ¼ inch off the top of the garlic bulb.
-
Place the heads of garlic onto a piece of tin foil and drizzle with olive oil, and sprinkle with salt.
-
Tightly wrap the garlic in the foil.
-
Roast in the oven for 40 to 60 minutes.
-
When cool to touch, remove the garlic cloves from the skin and set aside. You can squeeze the cloves out or simply peel the skin off. Set aside.
For the Caramelized Onions
-
Add the onions and sauté for 5 minutes or until the onions have softened.
-
Add the salt, if using, and reduce the heat to medium low and cook for 50 to 60 minutes. Stir the onions with a wooden spoon or spatula every few minutes, or until the onions are golden brown, and caramelized.
For the Potatoes au Gratin
-
In a small pot on medium low heat, melt the butter before adding the flour, bit by bit, and stir until evenly combined. Cook for a minute.
-
Slowly pour in the chicken broth and whisk until combined.
-
Slowly add in the milk, and whisk until combined.
-
Add the salt, pepper, and fresh herbs and allow fresh herbs to infuse for 2-3 minutes on low heat, stirring constantly. Do not let it come to a boil. Remove from heat and remove fresh herbs before setting aside.
-
Spray a 9×9 or 9×13 baking dish with non-stick spray.
-
Spread half of the sliced potatoes in an even layer on the bottom of the pan and top evenly with the caramelized onions, roasted garlic, and half of the béchamel sauce. Top with half of the cheese.
-
Layer the rest of the sliced potatoes on top before adding the rest of the béchamel sauce and cheese.
-
Cover with tin foil and bake for bake for 45 minutes. Remove the tinfoil and bake for another 30 minutes, or until the potatoes are cooked through.
-
Let rest for 15 minutes before slicing and serving. Top with some fresh thyme if desired.
Notes
- You can mash the roasted garlic into a paste and mix it into the béchamel sauce.
- Recipe adapted from Craving Home Cooked.
Nutrition
Calories: 496kcal | Carbohydrates: 57g | Protein: 17g | Fat: 23g | Saturated Fat: 12g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 8g | Trans Fat: 1g | Cholesterol: 54mg | Sodium: 593mg | Potassium: 1167mg | Fiber: 6g | Sugar: 15g | Vitamin A: 619IU | Vitamin C: 49mg | Calcium: 386mg | Iron: 3mg
Other places to connect with me
@carmyshungry on Instagram
Facebook
Shop my Amazon faves
Email: [email protected]
