Colcannon Gratin with Whiskey Caramelized Onions and Melted Dubliner

COLCANNON GRATIN: Changing Things Up A Bit

This Colcannon Gratin is sure to impress! It’s rich and creamy with robust flavors, and tastes just as good as it looks.

Colcannon purists beware… I’m sure I’ve broken some rules (if colcannon rules do, in fact, exist), but I offer no apology. I love cabbage and onions, and I most certainly love potatoes. So on that St. Patrick’s Day years ago when I decided to cook some seriously Irish-inspired dishes, it’s no surprise that colcannon was a priority.

Over the years, I tried different colcannon recipes and worked with different ideas. Eventually, this “hybrid” became our house favorite!

This post was originally published March 2017. Updated March 2022 and March 2023.

WHAT IS A GRATIN?

Whether you pronounce it “grah-tin” or “grah-taahn”, a gratin is baked (and then broiled) in shallow dish. Cheese or breadcrumbs are grated or crumbled on top at the final stage of cooking. The dish is then placed under the broiler until the toppings are melted and lightly browned and crispy.

WHAT’S TO LOVE ABOUT THIS COLCANNON GRATIN?

Underneath it all, milk and butter do a little dance with the other ingredients creating all kinds of creamy goodness. But in this case, you brown the butter first and add whiskey to the mix. Layer it all together, and then melt some delicious Dubliner cheese over the top until the edges become golden brown. Now you’ve really got something special!

Think French onion soup – but not French, and not soup. Just the rich, buttery, dreamy onion-filled flavors of the soup. Then imagine the velvety potatoes and just a hint of texture from the cabbage… It all goes together so very well in this version of colcannon.

MAKE IT AHEAD

On top of it all, would you believe this decadent dish can also be made ahead of time if you’re planning on serving it for a gathering? It can, indeed. I’d never lie to you about something as important as being able get ahead of the entertaining game.

I’ve tested it numerous times (mainly as an excuse to make this again and again because it’s that good), and it bakes up like a dream.

It’s best within a day, but it can be made up to three days in advance. (Yes, really!) Just make the recipe according to the steps below, spoon it into a casserole dish or terrines, add the onion/cabbage layer, cover, and refrigerate.

To prepare, uncover and allow the dish(es) to warm up a bit at room temperature. If using terrines like I did here, put them on a baking sheet (so they’re easier to move around and it’s easier to add the cheese with less mess later). Bake at 350 degrees F for 20 minutes or until warmed through. Then carefully remove gratin from the oven and turn on the broiler. Grate the Dubliner cheese over the top, and pop it under the broiler for 3 – 5 minutes or so until the cheese is melted and nicely browned.

ENJOY!

Print

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!

Cuisine Side Dishes

Prep Time 30 minutes

Cook Time 45 minutes

Total Time 1 hour 15 minutes

Servings 7 cups

Author Michele Phillips, BaconFatte.com

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

1. Preheat oven to 350 degrees.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. Remove gratin from the oven and turn on the broiler.

8. 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.

9. 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.

10. 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!

Making this Colcannon Gratin recipe?

I’d love to hear about it! Feel free to leave a note here in the comments below, or share your creations on Instagram, Facebook, and Pinterest.

Make sure to hashtag #baconfatte or tag @baconfatte in your social media posts!

Thanks so much for visiting! Please feel free to SHARE this recipe to your favorite social media channels… Just click the buttons below!

LIKED THIS? FEAST ON THESE:

Easy Sweet Potato Gratin Mashed Potato Corn Kraut Gratin Roasted Beet Tartlettes with Brandy Caramelized Onions and Goat Cheese Stir Fried Wild Rice – aka Minnesota Fried Rice Mixed Chimichurri Salad with Beans, Cherry Tomatoes, Green Onions and Lettuce Asian Rice Noodle Vegetable Stir Fry Bavarian Sweet Potato Salad with Kraut Warm Roasted Cabbage Salad Turkey Burger Rachel Sandwich Mashed Green Pea Spread with Lemon, Chives and Garlic