Frozen mixed vegetables potatoes au gratin is the perfect easy family dinner. With only 10 minutes of active prep time, enjoy easy potatoes au gratin with vegetables as your next holiday side dish or quick weeknight meal.

There are so many things I love about this recipe: It’s comforting, it’s simple, and my whole family loves it. This easy frozen mixed vegetables potatoes au gratin recipe is perfect for quick, family-friendly meals — especially when you haven’t been able to make it to the market!
This easy recipe was actually quite the creation. I was originally craving some delicious pesto potatoes gratin, also made with sweet potatoes and frozen vegetables, but an unexpected snow storm prevented me from making it to the grocery store.
I decided to scour my pantry, found potatoes, frozen veggies, and cheddar cheese, and voila! This cheesy potato casserole was born.
Ingredients for frozen mixed vegetables potato au gratin
The ingredients for this easy vegetable au gratin recipe are super simple! You’ll need just a cup of mixed frozen vegetables, so not even a whole bag, plus 4 medium-sized potatoes.
I decided to mix things up with a few yellow potatoes and a sweet potato (mostly because that’s what I had in my pantry at the time). The frozen mixed vegetables au gratin recipe also calls for milk, whole flour, pesto, and grated cheddar cheese.
How to make frozen mixed vegetables potato au gratin
Step 1. First, go ahead and preheat your oven to 400 degrees F. Next, set out an 11” oven-safe casserole dish. Then grease the bottom of the dish with butter or spray, if needed. For example, in my enamel pan, greasing is unnecessary.
Step 2. Now it’s time to prep the potatoes. First use a mandoline to slice the potatoes thin, up to ¼-inch thick. You can slice them all the same thickness, or vary the thickness like I do in the recipe video.
It doesn’t really matter, but sometimes I change it up! In the video, the bottom layer of potatoes is ¼-inch thick and the top layer of potatoes are sliced paper-thin. Either way, it will bake just fine.
Step 3. Now add a layer of half the potatoes to the casserole dish. You can do a mix of both yellow and sweet potatoes, or do one type of potato in this bottom layer, the other type on top. Again, it doesn’t matter – whatever you’re in the mood for!
Step 4. After that, add a layer of half the mixed frozen vegetables.
Step 5. Then add the rest of the potatoes, without overflowing the casserole dish.
Step 6. Next add the rest of the mixed frozen vegetables.
Step 7. Now whisk together the milk, flour, and pesto. Then pour the pesto milk mixture over the potatoes, sweet potatoes, and frozen veggies, without overflowing the casserole dish.
Step 8. Finally, top with cheddar cheese and bake in the oven, covered with foil, for 30 minutes. Then remove the foil and cook for another 20-30 minutes, or until the potatoes are easily pierced with a fork.
Want another really easy meal for your family? See tips for using store bought alfredo sauce to make a tasty dish for your family. Create restaurant style pasta with alfredo sauce from a jar. Use any store brand.
FAQs
What kind of potatoes for potatoes au gratin?
I used a mixture of sweet potatoes and yellow potatoes for this recipe, but you can certainly substitute other types. The key to potatoes au gratin is making sure to get a thin, mandoline slice.
Can I use fresh vegetables for this recipe?
Definitely! I like to use frozen mixed vegetables for ease and to save time. If you prefer to use your own favorite fresh veggies, simply layer them into the potatoes au gratin instead.
What can I substitute for pesto?
I like to mix in pesto to the milk to flavor this dish, but you can also use 1 tablespoon of your favorite Italian spice blend instead.
Final tips for making frozen mixed vegetables potato au gratin
- Use 1″ diced frozen vegetables. It’s best to use frozen vegetables that are diced in 1” segments. I used a variety of corn, peas, peppers and carrots. You can throw in some fresh veggies the same size or substitute them in this recipe as well.
- Make frozen mixed vegetables potatoes au gratin ahead. This is the perfect meal prep dinner! Simply construct and layer your potatoes au gratin with frozen vegetables, refrigerate or freeze, then pop into the oven when you’re ready to eat. Super simple prep, super simple clean up, super successful family dinner.
- Don’t forget the leftovers. This easy weeknight dinner recipe tastes just as good the next day! Refrigerate your leftovers for 3-4 days and reheat throughout the week for a quick work from home lunch.
- Feeding a crowd. This recipe can be easily doubled or tripled depending on the number of people you are feeding. Remember not to overstuff your baking dish, though! I would recommend making multiples instead of trying to make one huge casserole.
For more tasty recipes with potatoes, see my guide to potato side dishes.
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Frozen Mixed Vegetables Potatoes Au Gratin Recipe | Sip Bite Go
Ingredients
- 3 yellow potatoes medium, peeled
- 1 sweet potato medium, peeled
- 1 cup mixed frozen vegetables
- 1 cup milk
- 1½ tbsp flour whole
- 2 tbsp pesto
- 1 cup cheddar cheese freshly grated
Instructions
- Preheat the oven to 400 degrees. Set out an 11” oven safe casserole dish. Grease the bottom of the dish with butter or spray if desired. In my enamel pan, greasing is unnecessary.
- Prep the potatoes. Use a mandoline to slice the potatoes thin, up to ¼” thick. You can slice them all the same thickness, or vary the thickness like I do in the recipe video. It doesn’t really matter, but sometimes I change it up. In the video, the bottom layer of potatoes is ¼” thick and the top layer of potatoes are sliced paper-thin. Either way, it will bake just fine.
- Add a layer of half the potatoes to the casserole dish. You can do a mix of both yellow and sweet potatoes, or do one type of potato in this bottom layer, the other type on top. Again, it doesn’t matter – whatever you’re in the mood for!
- Add a layer of half the mixed frozen vegetables.
- Add the rest of the potatoes, without overflowing the casserole dish.
- Add the rest of the mixed frozen vegetables.
- Whisk together the milk, flour, and pesto. Pour the pesto milk mixture over the potatoes, sweet potatoes, and frozen veggies, without overflowing the casserole dish.
- Top with cheddar cheese and bake in the oven, covered with foil for 30 minutes, then with foil removed for another 20-30 minutes until potatoes are easily pierced with a fork.
Video
Notes
- Use 1″ diced frozen vegetables. It’s best to use frozen vegetables that are diced in 1” segments. I used a variety of corn, peas, peppers and carrots. You can throw in some fresh veggies the same size or substitute them in this recipe as well.
- Make frozen mixed vegetables potatoes au gratin ahead. This is the perfect meal prep dinner! Simply construct and layer your potatoes au gratin with frozen vegetables, refrigerate or freeze, then pop into the oven when you’re ready to eat. Super simple prep, super simple clean up, super successful family dinner.
- Don’t forget the leftovers. This easy weeknight dinner recipe tastes just as good the next day! Refrigerate your leftovers for 3-4 days and reheat throughout the week for a quick work from home lunch.
- Feeding a crowd. This recipe can be easily doubled or tripled depending on the number of people you are feeding. Remember not to overstuff your baking dish, though! I would recommend making multiples instead of trying to make one huge casserole.
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