Colcannon is a traditional Irish side dish that you’re going to love! Caramelized onions and cabbage mixed with creamy mashed potatoes!

Making a feast for St. Patrick’s Day? Don’t forget our Crock Pot Corned Beef along with one of our new favorites, this Fried Cabbage with Bacon! A traditional St. Patrick’s Day feast cooked right at home.

Colcannon in a black bowl with napkin

Colcannon – Mashed Potatoes with Cabbage & Caramelized Onions

I have to tell you guys, when we came up with the idea to make Colcannon for St. Patrick’s Day it really didn’t thrill me. But man, was I wrong. Colcannon is pretty much the best version of a mashed potato recipe that I’ve ever tried.

Of course, you’ll make your basic, creamy mashed potatoes all the time, but if you’re looking for a kicked up version, this recipe is it. Colcannon goes perfectly with your corned beef dinner but also with a nice, juicy steak or chicken!

How To Make Colcannon

Start by cooking down a ton of onions until they are super sweet, browned and caramelized.

Caramelized onions for a mashed potato recipe

Once the onions are caramelized, this will take about 20 minutes, you can see how much they reduce in size. I could eat these onions right out of the skillet, they are super sweet and so delicious.

While you’re cooking down the onions you can make the mashed potatoes by boiling peeled and cubed potatoes until fork tender, then draining and returning to the pot. Mash the potatoes with salt and pepper, cream or milk and butter, and then they can hang out until your onions and cabbage are ready.

Caramelized onions for making Colcannon recipe

After the onions get a good head start you can add in the sliced cabbage. The cabbage doesn’t take as long to cook down as the onions do. Plus we’re only looking to soften the cabbage, not caramelize it, so it only needs about 5 minutes.

Once you have the onions and cabbage cooked down and seasoned, stir them into the mashed potatoes just like you see here. Add a little more butter, just because, and taste for seasonings.

Now prepare to be blown away by the most amazing bite of mashed potatoes that you’ve ever put into your mouth.

Mashed potatoes with butter in a pot

Can You Make Colcannon Ahead Of Time?

You can make this mashed potato recipe ahead of time and gently warm it back up on the stove. You might have to add a little more cream and/or butter while you’re heating it back up.

Also these mashed potatoes will stay pretty warm covered on your stove, so even if you make them and leave them sitting for 30 minutes or so, they’ll still be warm enough to serve. The other thing you can do is make this Colcannon recipe and then transfer it to a slow cooker and turn it on the “keep warm” setting until you’re ready to serve.

Mashed potatoes with caramelized onions and cabbage in a black bowl

What Other Sides Can I Serve On St. Patricks’ Day?

Oh we’ve got you covered for side dish recipes. Once you’ve got your corned beed going in your slow cooker, move on to making a few (or all!) of these side dishes!

Colcannon mashed potatoes with a spoon in a bowl

Looking For More Potato Recipes?

Colcannon in a black bowl with napkin


  • Author: Dan
  • Prep Time: 15 minutes
  • Cook Time: 30 minutes
  • Total Time: 45 minutes
  • Yield: 6 servings 1x

This traditional Irish potato recipe has become a family favorite! Caramelized onions and cooked cabbage mix in with buttery mashed potatoes. Perfect for your St. Patrick’s Day feast!



  • 6 tablespoons butter, divided
  • 1 tablespoon olive oil
  • 2 cups thinly sliced yellow onion
  • 1 teaspoon salt
  • 1 teaspoon sugar
  • 1 pound thinly sliced cabbage
  • 3 pounds russet potatoes, peeled and cut into cubes
  • 1 cup half and half, cream or whole milk
  • Fresh black pepper to taste
  • Chopped chives and fresh parsley for garnish (optional)


  1. Add the oil and butter to a large skillet over low heat. Add the onions salt and sugar, stirring into the butter and olive oil. Cook for 20 minutes (stirring often so the onions don’t burn) until the onions are caramelized and brown.
  2. While the onions are cooking, boil the potatoes for 20-25 minutes until fork tender. Drain and return the potatoes back to the pot. Add 4 tablespoons of butter and 1 cup of half and half. Mash the potatoes until smooth and cover to keep warm.
  3. Turn the heat up on the skillet to medium. Add the sliced cabbage to the skillet, stirring to combine with the onions. Season the cabbage with a pinch of salt to help it wilt, cover and let the cabbage steam for 5 minutes. Remove the lid and toss the cabbage and continue to cook for another 5-7 minutes until the cabbage is completely wilted.
  4. Add the cabbage and onions to the mashed potatoes and stir to combine. Season with salt and pepper to taste and serve.
  • Category: Side Dish
  • Method: Stove Top
  • Cuisine: American

Keywords: mashed potatoes, colcannon, caramelized onions, st. patrick's day recipes, mashed potato recipes, potato recipes, potato side dish


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