Colcannon is the traditional Irish dish of mashed potatoes and cabbage or kale. Since it varies from region to region and is rarely made the same way twice, feel free to substitute your favorite leafy green for the cabbage or kale. It is equally good with spinach or chard.
- 2 pounds Yukon Gold potatoes, peeled and cut into chunks
- 1 leek, white and pale green parts, washed and sliced thin
- 6 tablespoons butter
- 2 tablespoons flour
- 2 1/2 cups milk
- 1/2 cup grated Parmesan
- 2 tablespoons Dijon mustard, or to taste
- 1 tablespoon cider vinegar
- 1/4 cup minced parsley
- 1 teaspoon salt, divided
- 3 cups (about 1 pound) cooked chopped cabbage
- 3 cups (about 12 ounces) cooked corned beef, cut into bite-size pieces
Preheat oven to 350 degrees F. Butter an 11 x 7-inch baking dish.
Combine potatoes, leeks, and water to cover in a large saucepan. Bring to a boil over high heat. Reduce heat; simmer, covered, 15 minutes, or until tender. Meanwhile, melt 2 tablespoons of butter over medium heat in a saucepan. Add flour; cook, stirring, 3 minutes. Add 2 cups milk; simmer, stirring, 5 minutes, or until lightly thickened. Stir in half the Parmesan, the mustard, cider vinegar, parsley, and half the salt.
Drain potatoes. Return to saucepan and coarsely mash. Add remaining 1/2 cup of milk, 2 tablespoons butter and remaining salt.
Spoon cabbage into buttered baking dish; cover with half the sauce. Top with corned beef and cover with remaining sauce. Add mashed potato mixture, smoothing it into an even layer, sprinkle with Parmesan, and dot with remaining butter. Bake 25 to 30 minutes, or until lightly golden.