Preheat your oven to 400°F (204°C) and spray a 9x13” baking dish with non-stick spray.

Spread sliced russet potatoes evenly across the bottom of the baking dish, then layer cooked Italian sausage and crispy bacon on top.

Warm reserved bacon grease in a large skillet over medium heat; add chopped onions and garlic paste and sauté until onions are translucent, about 2-3 minutes.

Stir in chopped kale and cook until wilted, about 3-4 minutes.

Sprinkle flour over the kale mixture, stir to combine, and gradually whisk in chicken broth until slightly thickened.

Pour in heavy whipping cream and stir until well combined.

In a separate bowl, beat an egg and whisk in a bit of hot sauce to temper it; mix the tempered egg into the sauce.

Mix half of the grated Parmesan cheese into the sauce until melted; pour over the layered potatoes and meat.

Cover with aluminum foil and bake for 50-60 minutes until potatoes are fork-tender.

Remove foil, sprinkle remaining Parmesan cheese on top, and bake uncovered for an additional 25-30 minutes until cheese is bubbly and golden.

Let casserole rest for 10 minutes before serving.