Green Bean Mashed Potato Casserole is a great Thanksgiving or Christmas side dish! Combining your 2 favorite dishes into one, you’ll love how this tastes. You can make the base plain or use garlic mashed potatoes to amp up all the flavors, either way it is a delicious duo.
Have you ever had green bean mashed potato casserole? No?? Oh you’re missing out! Yes you can make taters and this popular Thanksgiving side dish separately, but stop. You need to make them together this year! (originally published 10/21, affiliate links present)
Potato Onion Green Bean Casserole
There are a lot of great Thanksgiving side dish ideas out there. Most are traditional and kinda’ boring, this is NOT! Everyone needs a “wow, what is that” dish next to the moist turkey every year.
The great thing about this combo side dish is you can customize it. If you love extra creamy, add more sour cream to your bottom layer. Want to use canned onions you can, but homemade is best. We’ll show you how to make those too.
Mashed Potato Breen Bean Casserole
I know these are your top two must have items on your buffet table right? Why go boring though? This is an easy way to amp it up and make people say wow.
- Green beans and large bowl to mix ingredients
- frozen is best
- could use green beans drained
- Cream of mushroom soup
- Salt and pepper
- To make green bean casserole in the oven
- Sour cream
- Bacon bits
- For mashed potatoes it is easiest to make ours in the pressure cooker
- If you want to cheat you can use packaged Idahoan buttery boxed
Beef Potato and Green Bean Casserole
I included my favorite recipes for these two above. If you have your own favorite way to make these two dishes go right ahead and use your method. I use my Instant Pot for basically everything so preparing each is super quick. You could even brown some ground beef and add a layer of that in the middle.
- Then top with your crunchy onions and give it a quick trip in the oven to all meld together and brown.
I’ve even made sweet potato casserole in an Instant Pot before. It just saves you so much room in your oven to eliminate side dishes. It makes for an easier cleanup for me too.
I must admit though, I have a few of them. If you only have one you’d have to pick and choose. Crockpot side dishes are great to take advantage of too if you have a large crowd.
Cheesy Potato Green Bean Casserole
Once you whip together both dishes you’re going to layer them. Now if you have a big group I might double your typical recipe and use a 9×13 pan. We used a 2 quart casserole 8×8 baking dish here. I love something on the very top. Either crispy onions or cheese is our go to.
- Like I said, there is a lot of twists you could make to this. Add hatch green chiles for a little heat, or a lot. I like to add a can of mild to just about everything for flavor. It doesn’t make it hot.
- I do this many times inside my cream corn casserole recipe and it makes it over the top.
Mashed Potatoes and Green Beans
Steps to take for mashed potato casserole First you’ll want to have your flavored mashed potatoes prepared, as well as your slow cooker green bean casserole (or other method).
Mashed Potato Topped Green Bean Casserole
- Then spray your casserole dish with non stick spray
- I like to put my veggie dish on top with prepared mashed potatoes on the bottom
- you could do it the other way around I suppose
- Preheat oven to 350 degrees
- Sprinkle fried onions on top
- Can sprinkle a bit more salt and pepper on the very top for added flavor
- Bake for 20 minutes or bake for 30 minutes or until hot and lightly browned on top. Timing will depend on how thick yours is.
- If it’s already as hot as you’d like you can skip baking and just adjust your oven to broil to brown the top
- Remove from oven and stir casserole if desired. I like to leave as is so you can see the layers. I think it’s prettier that way.
Other side dishes you might like are: Our air fryer mashed potatoes can be made with sweet potatoes too.
- Best twice baked potatoes ever are here along with steamed green beans
- Sweet ambrosia recipe is something that must be on our holiday table
- 5 minute gravy can be made with any drippings from your turkey or chicken
Alterations you could make to our green bean mashed potato casserole recipe.
- Brown ground beef and put a layer of that in the center of the two.
- Sprinkle bacon bits on the top.
- Put a layer of leftover ham, diced, in between the two.
Want to see a few of my favorite things that I am totally obsessed with?? Take a peek and see how many you might already have…twinsies!
Green Bean Mashed Potato Casserole
- 1 9×13 pan
- Prepare your green bean casserole ingredients (minus the fried onions you'd put on top) + have your homemade fried onions or canned ready for assembly. Then make your mashed potatoes either on the stovetop or pressure cooker using link above in recipe card.
- If making stovetop mashed potatoes bring a pot of water to boil on the stove and put in your cubed and peeled russet or Yukon gold potatoes.
- Boil until they are fork tender. Drain and put them back into the pot, remove from heat.
- Add butter and cover so it melts. Then mash and slowly incorporate milk and salt until smooth. Taste to see if you'd like more salt or pepper added.
- Preheat oven to 350 degrees. Put mashed potatoes into a 8×8 pan and evenly spread out. Then add your layer of green bean casserole mixture topped with your fried onions.
- Place in the center of your oven for 20 minutes. Allow to cool slightly before spooning out and serving.