Scottish Rumbledethumps (Scottish Potato and Cabbage Casserole)

5 medium russet potatoes (about 2 pounds), peeled and roughly chopped
1 tablespoon kosher salt, plus more to taste
10 ounces savoy cabbage, cored and thinly sliced
1/2 cup (1 stick) unsalted butter
1 teaspoon freshly ground black pepper, plus more to taste
3/4 cup ( 3 ounces) grated cheddar cheese

Preheat the oven to 350°F.

Boil the potatoes and cabbage:
Place the potatoes in a large pot. Add enough cold water just to cover the potatoes, then add the salt. Cover and bring to a boil over medium-high heat. Once boiling, set a timer for 15 minutes. When the timer goes off, add the cabbage to the pot with the potatoes and let cook for another 8 minutes.

At this point, the potatoes and cabbage should be soft but not mushy. Drain well in a colander, then add them back to the pot you boiled them in.

Mash and season:
Add the butter to the pot with the vegetables and mash roughly. You’re not looking for a smooth mixture, you still want some chunks for texture. Season with salt and pepper to taste, then transfer to an 8-inch square baking dish (you can also use a 9-inch round baking dish).

Bake and serve:
Cover the entire surface with grated cheddar cheese, then bake until the top is golden brown, about 45 minutes. Let rest for 5 minutes before serving.

Leftovers can be left to cool to room temperature, then covered or transferred to an airtight container and stored in the refrigerator for up to 3 days.

To reheat, pop it by the portion in the microwave or transfer to an ovenproof baking dish, cover with foil, and bake at 350°F, until hot all the way through.