Scalloped potatoes gratin with pesto? Yes, please! If you love cheesy potatoes and pesto, you’ll be so pleased with this super easy potatoes gratin with pesto and peas and caramelized onions. Yup – it was the goal to get all of those tasty things in one dish…
Mission accomplished!
It’s packed with flavor in each bite from the savory, cheesy center to the bubbling crunchy top. It requires a little prep but is an easy make-ahead potato side dish.
Quick facts about baking potatoes gratin with pesto
- Bake time is one hour.
- Use any easy to melt cheese.
- Leftovers are phenomenal.
All this is making me hungry – let’s get to making this potato gratin with store-bought pesto.
What you need to make pesto potatoes gratin
This recipe starts with making a quick batch of caramelized onions (onions, olive oil, salt). You could use raw onion, but it will get steamed instead of having that deep caramelized flavor.
Then all the usual suspects go in the casserole – russet potatoes that are peeled and sliced thin with a mandolin, cheddar cheese, mozzarella cheese, and peas to give it a pop of green and check off the “vegetable” box for this dish.
The liquid is where it gets fancy and turns into a richly flavored pesto potatoes gratin. Milk, flour, and pesto are whisked together then poured over the potatoes.
Although you can make your own pesto with fresh herbs, using store-bought pesto to make potatoes gratin will make your scalloped potatoes gratin with pesto recipe come together extra-fast.
Recipe overview
Caramelize onions first. Add diced onions, olive oil, and salt to a small pan on medium heat on the stove. Stir onions regularly for 5-10 minutes until they are caramelized and turn golden brown. See the potatoes gratin with pesto recipe at the bottom of this page for tips on if the onions start to burn.
Love onions? Me too. See this step by step guide for red wine carmelized onions. And this one for caramelized onions sous vide in beer.
Whisk together the milk, flour, and pesto, and set aside.
Grease the bottom of a cast iron skillet or a baking dish with butter or cooking spray. Choose a vessel that will hold all the potatoes because they don’t cook down very much.
I used a oval-shaped 9” cast iron dish.
Add half of the potatoes to the baking dish.
Then add half of the filling ingredients: caramelized onions, cheddar and mozzarella cheese, and peas. Add the rest of the sliced potatoes so they are about level with the top of the dish.
Pour the milk mixture over the potatoes until the liquid is about level with the potatoes.
Add the rest of the filling / topping.
Baking potatoes gratin in the oven
Bake potatoes gratin at 400 degrees for one hour, until the cheese is bubbling and brown. When cooked completely, the potatoes can easily be pierced with a fork.
They will be smooth like butter – – not stiff at all – – if they are fully cooked.
How long to let potatoes gratin cool before serving
Let cool and set for 15-30 minutes before serving. The longer you wait, the easier it will be to cleanly cut and remove the potatoes gratin from the casserole dish.
The potatoes are usually still nice and warm if you wait 30 minutes. You can also cover the casserole dish with tin foil if desired.
This is an easy potatoes side dish to serve with blackened chicken salad sandwiches, sous vide chicken or make-ahead Mexican salad.
Tips for making this tasty potato side dish
- Use a mandolin to thinly and uniformly slice the potatoes. I used the first 1-2 settings. The potatoes cook faster if you thinly slice them, and uniform slices means uniform, even cooking.
- The vessel I used is an oval-shaped 9” cast iron dish.
- It’s easy to substitute the frozen peas in this potatoes gratin recipe for other frozen veggies like diced carrots or corn. Shoot for something that’s similar in size.
- For pesto sauce, the one used here is from Freak Flag Organics, from a giveaway I did with them along with my sous vide cookbook.
- Try making your own homemade spinach basil pesto — it’s so easy!
- Don’t have pesto sauce? Try a little garlic Alfredo sauce instead.
- Cheeses can be switched out too– other options I enjoy are fontina and gruyere.
- This dish is easy to reheat. Just stick it in the oven at 400 degrees for around thirty minutes, until warmed through.
If you need me, I’ll be in the kitchen licking my fork clean
I’m on a potato gratin kick right now.
This casserole is one of my favorite potatoes and pesto dishes, and I hope it’ll become one of yours. It’s in my go-to repertoire: not only does it taste phenomenal, it’s also easy to memorize after a couple times making it. I love when I get to know a recipe so well I can make it without instructions.
Are you a foodie, too?
Find me on Instagram @sipbitego. I love seeing photos of delicious food.
Cheesy Potatoes Gratin With Pesto And Peas Recipe [Sip Bite Go]
Video
Ingredients
- 1 tbsp butter
- 3 russet potatoes peeled and sliced thin
- ½ cup cheddar cheese freshly grated
- ½ cup mozzarella cheese freshly grated
- ¼ cup peas frozen
- 1 cup milk
- 1.5 tbsp flour
- 2 tbsp pesto
Caramelized onion filling (optional)
- ½ onion diced
- ½ tbsp olive oil
- ½ tbsp salt
Instructions
- Preheat the oven to 400 degrees.
- Caramelize onions first. Add diced onions, olive oil, and salt to a small pan on medium heat on the stove. Stir onions regularly for 5-10 minutes until they are caramelized and turn golden brown. If they begin to burn, add a little drizzle of olive oil. If they are burning really badly the heat is probably too high. Turn down the heat to medium-low to fix this and add 1 tbsp of water to lift the burnt onions from the pan. Then add a drizzle of olive oil and keep stirring until caramelized.
- Whisk together the milk, flour, and pesto, and set aside. Grease the bottom of a cast iron skillet or a baking dish with butter or cooking spray. Choose a vessel that will hold all the potatoes because they don’t cook down very much.
- Add half of the potatoes to the baking dish. Then half of the filling ingredients: caramelized onions, cheddar, and mozzarella cheese, and peas. Add the rest of the sliced potatoes so they are about level with the top of the dish.
- Pour the milk mixture over the potatoes until the liquid is about level with the potatoes. Add the rest of the filling/topping.
- Bake potatoes gratin at 400 degrees for one hour, until the cheese is bubbling and brown. Let cool and set for 15-30 minutes before serving.
Notes
- Use a mandolin to thinly and uniformly slice the potatoes. I used the first 1-2 settings. The potatoes cook faster if you thinly slice them, and uniform slices means uniform, even cooking.
- It’s easy to substitute the frozen peas in this potatoes gratin recipe for other frozen veggies like diced carrots or corn. Shoot for something that’s similar in size.
- Don’t care for pesto sauce? Try a little garlic Alfredo sauce instead.
- Cheeses can be switched out too– other options I enjoy are fontina and gruyere.
- This dish is easy to reheat. Just stick it in the oven at 400 degrees for around thirty minutes, until warmed through.
Jennifer says
Nothing like a heaping cast iron dish full of yummy, cheesy delights! That was good! Thank you!
Stacey says
Made this last night – loved it!!! Love how there were so many other veggies than just potatoes.. kids gobbled it up
Dannii says
You had me at cheesy potatoes. I love that you have added some veggies too.
Tracy says
Wow these are SO good. Our whole family loved it so much!!
Kathrn says
I can’t wait to try this — especially because you said the leftovers are phenomenal! I’m always looking for meals that can stretch!
Barbara says
Jenna, this is my second go about – following the directions this time with it coming out just right. Came to mind to include that this recipe indeed worked just fine with chicken stock instead of milk. That was the substitution hen I was in a pinch and I added more peas.