All quantities are approximate. I didn’t measure, just eyeballed it for “I like a lot of greens in the mix so it feels healthy because extra veggies”. 

  • 5 medium sized redskin potatoes
  • 1 bulb of roasted garlic OR two ice cube size pieces of frozen then thawed roasted garlic
  • 1 large leek, green and white parts included, washed and sliced in half lengthwise then in ¼ inch wide rounds.
  • About ¼ medium sized cabbage, chopped or shredded (the same as for coleslaw).
  • One 8 or 10 oz package of white, crimini, or portabella mushrooms, sliced
  • 2 to 3 tablespoons of butter
  • Drizzle of olive oil (optional)
  • 1 tsp of salt
  • 1 tsp ground pepper


If the garlic has not already been roasted, then place the garlic bulb in tinfoil, drizzle generously with olive oil, wrap tightly in the tinfoil and roast in the oven (on a cookie sheet) for about 35 minutes at 425 degrees. Let cool and squeeze out into a small bowl, set aside. NOTE: roasted garlic can be prepared ahead of time and frozen for when you need it. I freeze it in ice cube trays.  

Chop redskin potatoes into 1 inch chunks and add to a pot of water, boil until easily pierced with a fork. Drain into a bowl, reserving the potato water. 

Coarsely mash potatoes with a potato masher, add back a little of the potato water at a time to give them the consistency of thick mashed potatoes. Set aside.  

While the potatoes are cooking, sauté the mushrooms in the butter in a large pan until browned. Remove and set aside. 

In the same pan add and sauté the leek and cabbage, stirring regularly, until soft and slightly translucent. Add the salt and pepper while cooking. Add a drizzle of olive oil if they look like they need a little more oil for cooking.  

Once they are done, stir in the roasted garlic until thoroughly mixed together.  

Add the mashed potatoes and stir until everything is evenly mixed. 

Add the mushrooms and again stir until they are all mixed. (Adding the mushrooms last ensures that they don’t get all mushed up and broken during all the stirring, looks nicer for the presentation). 

Variations and Substitutions

Really, this is a base recipe. Increase or decrease the amounts of any ingredient to your taste. 

Use less butter or even substitute olive oil if you prefer.  

You can add or substitute kale for the cabbage.  

Use a large onion if you don’t have any leeks on hand. 

Add more mushrooms if you like, or eliminate them if you hate mushrooms.  

It’s okay to not roast the garlic, though I will note that the roasted garlic is AMAZING.  

It’s fine to substitute other kinds of potatoes, or even use instant mashed potatoes. For that matter, it’s fine to substitute rice for the mashed potatoes…. it won’t be “Colcannon” anymore, but it will still be tasty!

In this recipe there is no milk or sour cream in the mashies just because I forgot to add the milk, but it’s fine to use milk instead of the potato water for the liquid. 

Save the extra potato water: it’s great either added to a soup or as food for a sourdough starter. 

I’m a huge believer in gravy on mashed potatoes, but this does not even need gravy.  

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