2poundYukon gold potatoes, peeled and cut into 1-inch pieces
3 to 4cupschopped kale
Milk, for consistency (start with 3-4 tablespoons)
2shallots, finely minced or 1/2 cup finely chopped yellow onion
2clovesgarlic, finely minced or pressed through a garlic press
1 to 2cupschopped carrots, pretty hefty dice; don't chop them too finely
2cupslow-sodium chicken broth
3 to 4cupscooked chopped chicken, rotisserie chicken works great here as well (see note)
⅓cupfreshly grated Parmesan cheese, for topping
In a large pot of lightly salted water (I add a hearty pinch of coarse kosher salt to the pot), boil the potatoes until slightly tender but still firm, 7-9 minutes, depending on the size of the potatoes. Add the kale to the pot and simmer for 5-6 minutes. Drain into a colander and return to the pot. Add the garlic powder, butter and sour cream. Lightly mash, adding milk, a tablespoon or two at a time, until the potato-kale mixture is mashed and creamy (you can leave it as chunky or smooth as you want depending on your texture preference) - it should be spreadable without being too thin.
While the potatoes are boiling, get started on the filling. In another 3 or 4-quart pot, melt the 3 tablespoons butter over medium heat and add the shallots (or onions), garlic, and carrots. Stir well. Cover the pot and cook the vegetable mixture, stirring occasionally and moderating the heat to prevent sticking, for 8-10 minutes, until the carrots are slightly tender (they'll cook more in the next couple of steps).
Sprinkle the flour over the vegetable mixture and cook for 1-2 minutes, stirring often. Slowly add the chicken broth, whisking vigorously as it is added to prevent clumping - it helps to add 1/2 cup at at time, slowly, and let it bubble and thicken before adding more broth. Once all the broth is added and the sauce is smooth, whisk in the milk. Stirring constantly, bring the mixture to a simmer, and cook until the sauce is slightly thickened, 2-3 minutes.
Stir in the cooked chicken. Add salt and pepper to taste; I add about 1/2 teaspoon of each.
Preheat the oven to 400 degrees F. Lightly grease a 9X13-inch or slightly smaller baking pan. Pour the chicken filling into the pan evenly.
Dollop the mashed potato mixture over the top of the chicken mixture and using the back of a spoon or an offset spatula, spread it into a somewhat even layer; it's ok if it looks a bit rustic and uneven. I don't spread mine all the way to the edges - I leave about a 1/2-inch border all the way around but you can spread it into a thinner layer if desired.
Sprinkle the Parmesan cheese on top. Bake the casserole for 20-25 minutes until the edges are bubbling. Let rest 5-10 minutes before serving.
Make Ahead: this dish can be made, assembled, covered and refrigerated for up to 24 hours before baking and serving (you may want to add 5-7 minutes onto the baking time). I have not tried freezing it yet.Filling: to be super efficient, you can start making the filling while the potatoes are boiling.Chicken: Rotisserie chicken is perfect for this recipe, or you can use this simple stovetop method.Chicken Mixture:if you tend to shy away from recipes where you have to whisk in liquid like your life depends on it to prevent lumps, you might consider blending the 1/3 cup flour with the liquid and adding it to the carrot/onion mixture - then bring the mixture to a simmer, stirring, and cook until slightly thickened. It will alter the flavor just a bit (since the flour won't brown with the vegetables as it absorbs the butter and other flavors) but it's a viable option if it is more your style.