Colcannon Gratin with Whiskey Caramelized Onions and Melted Dubliner
A velvety Colcannon dish accented with whiskey and topped with melted Dubliner cheese. Make it ahead for a crowd - it’s absolutely delicious and sure to impress!
Ingredients
- 1½ pounds gold, waxy potatoes - peeled and cut into small, even chunks
- 1½ pounds Russet potatoes – peeled and cut into small, even chunks
- 6 Tbsp. salted butter – such as Kerrygold
- 2 pounds yellow onions – halved and thinly sliced
- 1½ pounds cabbage - approx. ½ lg. head, quartered and thinly sliced
- 4 ounces Irish Whiskey - divided
- 4 ounces whole milk at room temp
- 4 - 6 ounces Dubliner cheese
- 2 - 3 tsp. Kosher salt - divided + more to taste
- ½ tsp. ground black pepper + more to taste
- For garnish: fresh watercress, flat leaf parsley, chives, or other (optional)
Instructions
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Preheat oven to 350 degrees.
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Potatoes (1): Prepare a large stock pot with cold water. Scrub and peel the potatoes, cut into ½-inch cubes, and place cubes into cold water. Rinse potatoes two or three times to remove excess starch. Add enough fresh water to cover the potatoes along with one teaspoon of salt. Bring to a boil over medium heat.
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Onions & Cabbage: In a large, covered pan, add the butter and brown slowly over medium-low heat. Peel, halve, and thinly slice the onions, and add them to the pan with the brown butter. Partially cover the pan leaving a small space for steam to escape, and allow onions to sweat for about ten minutes.
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After the first ten minutes, add 2 ounces of whiskey to the onions, stir well, and partially cover. Check and stir the onions every ten minutes or so until they’re completely soft and golden brown – this should take 30 – 40 minutes. Quarter and cut cabbage into ½ inch thick slices. When onions are caramelized, add sliced cabbage and 1 ounce whiskey to the pan. Stir well and partially cover. Stir every 5 minutes or so, and check doneness. Cabbage should have a bit of texture in the finished dish.
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Potatoes (2): When potatoes are fork tender, drain completely and return to the pot. Pour 1 ounce of whiskey into the milk, stir, pour the mixture into the potatoes, and then mash well. Spoon about half of the caramelized onions and cabbage into the mashed potatoes and stir well to combine.
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Spoon mashed potato mixture into an oven safe casserole dish or terrines and top with the remaining caramelized onion and cabbage mixture. Season with black pepper, cover, and bake for 15 - 20 minutes or until potato mixture is heated through.
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Remove gratin from the oven and turn on the broiler.
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Sprinkle shredded cheese over the top of the hot potato mixture. Place gratin(s) under the broiler for 2 - 3 minutes, or until cheese is melted and lightly browned.
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To serve, grate more cheese over the top of the hot gratin (optional), garnish, and serve. *See notes below if preparing ahead and reheating gratin.
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Garnish with fresh watercress, chopped chives, or other greens, and enjoy right away.
Recipe Notes
*The weight of the potatoes and onions need not be exact.
*Peeling the potatoes is optional… I don’t usually peel them for this dish.
*The whiskey is, of course, optional but it adds a wonderful richness to the dish. It’s also optional to add more than the 4 ounces indicated, but if you’re adding it, doing so in stages as indicated – versus all at once – is a must for building layers of flavor.
*You can prepare this Colcannon Gratin up to three days ahead of time. Keep covered and refrigerated. Allow to warm slightly at room temp, then bake at 350 degrees for about 20 minutes until colcannon is completely warmed through. Add cheese and broil just until cheese is melted and toasty brown.
*It goes without saying, but I’ll say it anyway: Potatoes tend to hold heat for a long time. You’re going to be really excited for that first bite, but do be careful and make sure your colcannon isn’t too hot when you’re ready to eat!