Skip to Content

How To Fix Undercooked Mashed Potatoes | The Best Way

It is with a sinking feeling that you pour the water off the potatoes and start mashing them only to discover that they are not quite done. But, it is very fortunate that there are at least a couple of different things you can do to turn the mashed potatoes into the delicious dish that you anticipated.

The best way to fix undercooked mashed potatoes is to add a small amount of butter and milk and cook them over low heat in a saucepan on the stovetop for 5 to 10 minutes. You could also put them into an ovenproof pan and bake them for about 10 to 15 minutes to finish the cooking process.

If you are in a hurry, pour the undercooked potatoes into a microwave-proof dish and microwave on high in 5-minute increments until done.

In this article, I will discuss everything you need to know about preventing, dealing with, and correcting undercooked mashed potatoes.

How To Fix Undercooked Mashed Potatoes

Lumpy Mashed Potatoes in a Pot With a Potato Masher
Lumpy undercooked potatoes are no fun.

The number one thing to remember is that if you have already poured the water off the potatoes and then discover they are undercooked, you should not add more water to cook until done because the potatoes would then taste watery and the flavor would be ruined. But there are ways to fix this problem.

Can You Recook Undercooked Potatoes? 

You can re-cook undercooked potatoes. The 3 best ways to fix undercooked mashed potatoes are the following:

1. Finish Cooking On The Stovetop

The undercooked mashed potatoes can be put into a saucepan along with a little butter and milk and cooked for 5 to 10 minutes on the stovetop over low heat until the undercooked potatoes are fully cooked. They will need to be stirred constantly to prevent scorching or burning.

2. Bake Them In The Oven Until Done

Pour the undercooked potatoes into an ovenproof dish and bake at 350 degrees Fahrenheit for 10 to 15 minutes or until the potatoes are fork-tender. Once tender, you can then continue mashing and seasoning the potatoes.

3. Microwave The Undercooked Potatoes

Put the potatoes into a microwave-safe dish and microwave them on high in five-minute increments until the potatoes are done and can be mashed successfully to create fluffy mashed potatoes. Check after each five-minute period to prevent overcooking.

How Do You Soften Cooked Potatoes?

You can soften cooked potatoes by using one of the three methods mentioned above for re-cooking undercooked potatoes.

How Do You Tell If Potatoes Are Undercooked?

You can tell that potatoes are undercooked because they will have very firm lumps in them and will not mash completely.

To fix undercooked potatoes, use one of the methods mentioned above to re-cook the potatoes until done.

Bowl of Jelly Grandma's Mashed Potatoes
Perfectly cooked mashed potatoes, ready to eat.

How Can You Tell If Potatoes Are Fully Cooked And Ready To Mash?

You can test potatoes that you are boiling to make mashed potatoes by two methods:

  1. By sticking a fork into them to make sure they are fork tender. When you stick a fork into them and they are done, the potatoes will break apart into different pieces. Do not test the potatoes with a knife, because the knife may cut the potato giving you the false impression that it is done.
  1. I usually use a 2nd method to test my boiled potatoes and that is by tasting them. I take a piece of potato out of the pot, let it cool slightly, and taste it to make sure it is completely done. This is definitely the most foolproof method I know to make sure the potatoes are completely done.

What Can Cause Undercooked Potatoes?

The three main causes of undercooked potatoes are:

  1. Not cooking the potatoes long enough by just cooking them for a particular length of time and then just pouring off the water.
  2. Not checking the potatoes for doneness before pouring off the water and just assuming they are done.
  3. Starting the potatoes to cook by dropping them into boiling water, as this would soften the outside of the potatoes very quickly while leaving the inside uncooked.
Testing potatoes they are done when they split if pierced with fork
They are done if they split when pierced with fork.

How To Make Sure Mashed Potatoes Are Fully Cooked?

These are the steps to perfect, fluffy mashed potatoes:

  1. Peel and cut potatoes into chunks.
  2. Put the potato chunks on to cook by placing them into a saucepan or Dutch oven large enough to cook them properly without boiling over and cover them with cold water.
  3. Bring them to a boil over high heat, reduce the heat slightly, and cook until done.
  4. Test the potatoes for doneness by making sure they are fork tender and then do the taste test to make sure they are done all the way through.
  5. Pour off the water and add butter to the hot potatoes to melt and begin mashing with a fork or potato masher.
  6. Add milk, a small amount at a time, and finish mashing with a mixer for a lighter, fluffier texture.
  7. Season to taste.
Whipping mashed potatoes with mixer
Keep mixing and adding milk until perfect.

What Is The Best Way To Reheat Mashed Potatoes?

Even though mashed potatoes can be reheated in a pot on the stovetop or in a pan in the oven, the best way to reheat without scorching them is in the microwave.

When mashed potatoes are reheated, they need liquid of some sort, usually milk or cream, added to them as they become thicker as they cool, and they need to be stirred briskly so that they are reheated all the way through.

Why Are My Mashed Potatoes Like Glue? 

Having mashed potatoes turn out like glue rather than light and fluffy as they should be can be caused by a number of different things.

  • The main thing that causes mashed potatoes to turn out like glue is the type of potato used. Russets are the best type of potatoes to make light and fluffy mashed potatoes. Red potatoes are better roasted.
  • Another thing that causes gluey mashed potatoes is over processing. Mashing them too much by using a mixer or food processor and not mashing them at all by hand will cause the texture of the mashed potatoes to take on a gluey, sticky texture.
Partially peeled russet potatoes on a blue plate
Try using Russets for fluffy mashed potatoes.

How Can I Fix Mashed Potatoes That Turn Out Like Glue?

If your mashed potatoes turn out like glue, there is no way to fix them so that they do not have the sticky, gluey texture. But, there are other things you can do.

  • Even though some mashed potatoes turn out sticky and have a texture like glue, they still taste good and can be served as they are.
  • But, if you just don’t want to serve potatoes with that kind of texture, they can be baked with cheese on top for an excellent side dish.
  • Another dish that can be made with the sticky mashed potatoes is potato pancakes. All you have to add is egg, flour, and a few spices and then fry them up for a perfect potato pancake.

Final Thoughts

Undercooking mashed potatoes is a common cooking mistake that I suppose we have all been guilty of making at some point. If this happens when cooking an ordinary meal that only your family will eat, then it is no big deal, right? But suppose it is for a holiday meal and you will be serving to a large crowd, then you always want to put your best foot forward.

It is inevitable that you will at some point either have potatoes that are not cooked all the way through or that have the consistency of glue. But, either way, there are things from this article that you can do to either fix the problem or other dishes you can create from the “messed up” potatoes.

Thanks for stoppin’ by!

For more, don’t miss 11 Yummy Substitutes for Milk in Mashed Potatoes.