Preheat your oven to 400°F (200°C) and lightly spray a 9x13" baking dish with nonstick spray.

Spread the thinly sliced russet potatoes evenly across the bottom of the prepared baking dish.

Sprinkle the crumbled cooked Italian sausage and crispy bacon evenly on top of the potato layer.

In a skillet, heat the reserved 1/4 cup of bacon grease over medium heat, then add the chopped white onion and garlic paste, sautéing for 2-3 minutes.

Stir in the chopped kale into the skillet with the sautéed onions and garlic; cook for about 3-4 minutes until wilted.

Sprinkle in the flour and stir for 1 minute, then gradually whisk in the chicken broth and let it simmer for 5 minutes.

Once thickened, mix in the heavy whipping cream until fully combined.

In a separate bowl, gradually mix a small amount of the hot sauce into the beaten egg to temper it, then blend it back into the skillet.

Stir in half of the grated Parmesan cheese until melted, then pour this sauce over the layered ingredients.

Cover with aluminum foil and bake for 50-60 minutes, then remove the foil, sprinkle remaining Parmesan cheese and return for 25-30 minutes.

Let it rest for 10 minutes before serving.