Place the cubed potatoes in a large pot, cover with cold salted water, and bring to a boil over high heat. Once boiling, reduce the heat to medium and cook for 10 minutes.

Add the chopped curly kale directly on top of the boiling potatoes. Cover and continue to cook for an additional 5 minutes, or until the potatoes are fork-tender and the kale is wilted.

While the potatoes and kale cook, heat a large skillet over medium heat and fry the diced bacon until crispy and golden brown, about 6 to 8 minutes. Remove the bacon with a slotted spoon, leaving the rendered fat in the skillet.

In the same skillet with the bacon fat, sear the sliced smoked sausage over medium-high heat for about 3 to 4 minutes per side until lightly browned and warmed through. Remove from the skillet and set aside.

Drain the potato and kale mixture thoroughly, then return them to the warm pot. Mash them together using a potato masher, gradually pouring in the warm milk, butter, and Dijon mustard until smooth and creamy.

Gently fold the crispy bacon into the mashed potato mixture, then season with the freshly grated nutmeg, salt, and black pepper to taste. Serve immediately in shallow bowls, topped with the sliced smoked sausage and a drizzle of the remaining bacon fat from the pan.