Preheat the oven to 400°F (200°C). Gather your ingredients.

Grease a 9x13 inch baking dish with butter or cooking spray. Layer the thinly sliced Russet potatoes at the bottom.

In a skillet, cook the ground Italian sausage until browned for about 5-7 minutes. Add the crumbled bacon and mix.

Add the reserved bacon grease to the same skillet, warm it up, then sauté the diced white onion and garlic paste for 2-3 minutes.

Stir in the chopped kale to the onion and garlic mixture and cook until wilted, about 2-3 minutes.

Sprinkle in the flour and mix for about 1 minute. Gradually whisk in the chicken broth and simmer until thickened, around 3-5 minutes.

Beat the large egg in a small bowl, then slowly add some hot sauce to temper it. Stir the egg mixture back into the skillet.

Mix half of the Parmesan cheese into the sauce until melted, reserving the rest for topping later.

Pour the sauce evenly over the layered potatoes and meats in the baking dish.

Cover the baking dish with foil and bake for 50-60 minutes until the potatoes are tender.

Remove foil and sprinkle the remaining cheese on top. Bake uncovered for another 25-30 minutes until bubbling and golden.

Let the casserole rest for about 10 minutes before serving.