Peel and cut the russet potatoes into 1-inch chunks, then place them in a large pot and cover with cold water. Add 2 tablespoons of salt to the water—this seasons the potatoes from within and raises the boiling point slightly for faster, more even cooking. Bring to a boil over high heat and let cook for 15-20 minutes until the potatoes are completely tender and easily pierced with a fork. While the potatoes cook, finely shred the kale into 1/4-inch strips and slice the green onions, keeping the white and green parts separate.

Drain the cooked potatoes thoroughly using a colander, reserving the pot. Return the empty pot to medium heat and add the 8 tablespoons of unsalted butter, allowing it to melt completely. I like using Kerrygold butter here for that authentic Irish flavor and beautiful golden color. Add the shredded kale and cook for 3-4 minutes, stirring occasionally, until it's wilted and tender. The kale will release moisture and take on a glossy appearance as it cooks in the butter.

Stir in the white and light green parts of the sliced green onions and cook for 1 minute until fragrant and softened. Pour in the 1 1/4 cups of whole milk, stirring gently to combine. I use Borden whole milk for a creamier, richer texture that makes these colcannon-style potatoes truly luxurious. The milk will warm slightly in the butter and kale mixture, creating the perfect base for mashing.

Add the drained potatoes from Step 1 back into the pot with the kale and milk mixture. Using a potato masher, work through the potatoes with firm, deliberate strokes until you reach your desired texture—I prefer leaving some small chunks for a rustic, authentic Irish style rather than making them completely smooth. Continue mashing gently while folding in the greens and kale to distribute evenly throughout.

Taste the mashed potatoes and add the 1/4 teaspoon of black pepper, plus additional salt if needed—remember the potatoes were already seasoned during cooking, so add conservatively. Stir in the reserved dark green tops of the green onions for a fresh, oniony finish. Serve immediately in a warm bowl with an extra knob of butter melting into the top, which is the traditional Irish way to serve this comforting dish.