Box of Reser's Mashed Potatoes
Bowl of Reser's Mashed Potatoes with Parmesan cheese added
Container of Reser's Mashed Potatoes
Adding cheese to Reser's Mashed Potatoes

We tried some of the Main St. Bistro Mashed Potatoes from Costco one time and have been buying them ever since. These potatoes are neither lumpy nor mushy, but they are nice and creamy. They are especially delicious with Parmesan cheese added in. We sometimes freeze a package so it lasts longer (even though it says keep refrigerated), and it still tastes just as good.

This is how we usually cook the refrigerated mashed potatoes (both 26 oz boxes):

  • Warm up one of the mashed potatoes boxes in the microwave for 3 minutes
  • Put the mashed potatoes from first box into a bowl
  • Fold in shredded Parmesan cheese to taste while it's still warm (we usually use enough Parmesan cheese so that it covers the top of the potatoes)
  • Warm up the second box of mashed potatoes in microwave for 2 minutes
  • Add the mashed potatoes from the second box into the bowl
  • Fold in more shredded Parmesan cheese to taste
  • Let the bowl of mashed potatoes sit in the refrigerator overnight
  • The next day (or same day) -- put the bowl of mashed potatoes in the oven (325 degrees F) for 45 minutes to 1 hour... and enjoy!
  • As a side note the easiest way to make these mashed potatoes is just following the microwave instructions on the box. It takes less than 10 minutes, and they still taste good.

    Overall Rating:
    Food: Reser's Main St. Bistro Mashed Potatoes
    Source: Costco, Tucson, AZ
    Price: $5.99 for twin pack (two 26oz boxes)
    Rating: Good



    REVIEW – Reser’s Main St. Bistro: Mashed Potatoes from Costco

    • Buttockss

      My question to Marilyn. I bought mashed potatoes from Costco, and cooked them in the freezer, and they still tasted good.

    • Marilyn

      My question is i bought mashed potatoes drom costco and stuck in freezer are they still good to cook?

    • AmyB

      I have some frozen in my freezer right now. Got them at Costco and haven’t had them yet. My brother & his family love them.
      How donI cook them from frozen? Should I defrost in microwave first? I wonder which defrost setting I should use…
      TIA I realize this blog post is 6 yrs old, but I’d really appreciate the help. Googled but haven’t been able to find an answer.

      • Iceni

        Leave them overnight in the fridge after freezing then follow the packet instructions. Mix well, You can always microwave them a little longer. I would not recommend microwaving them from the frozen state. It takes a long time.

    • Linda McCaughey

      Excellent! and, yes–they freeze very well with no change in taste or quality.

    • Kristin

      Can I freeze the scalloped potatoes prior to cooking?

      • Jeanette Pollock

        I have the cheese scalloped potatoes frozen and need to serve for a party. Should I thaw them first or just bake in the oven?

        • Iceni

          Thaw them overnight in the fridge if possible. .They will taste better.

    • Jean

      Can you freeze mashed potatoes before expiration date?? Or is better to freeze after potatoes have been cooked?? Just wondering if anyone has tried this?? ThAnk you.

      • Lori Humphreys

        Did u try to freeze? Trying to figure out the same thing as I bought too many for a party

    • James White

      The scalloped potatoes were frozen when purchased. They were in the refrigerator display in the store. I tried to cook them on the day I bought them and they were frozen hard. They came out watery and bad. Never again.

    • James White

      These scalloped potatoes say’never Frozen.’ They we we sold in the refrigerated section of the local Costco store, took them straight home on a 92 degree day, opened the package to cook them the evening purchased and they were frozen harder than a rock. Tried to defrost in microwave before baking. Didn’t work. They were awful, the cream sauce had broken and turned to chunks curds and whey (like watery cottage cheese). Awful. I noticed that the use by date was just a few days away, were they frozen at some central Costco warehouse?

    • Sue

      Thought these mash potatoes would be good. They were atrocious. How these pass as potatoes I have no idea. Far too salty and did not have the texture of potatoes. Better to make own and freeze ahead before entertaining if you can’t make the same day. Talk about causing high blood pressure. Should be removed from shelves.

      • sue

        “better to make own” no kidding, what a stupid comment

    • Sue

      Does anyone know how to prepare the Main Street mashed potatoes in the crock pot?

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