Preheat oven to 200°C/400°F (for bacon). Line a large rimmed sheet with foil + rack. Lay 450 g bacon strips without overlapping. Bake 18–22 minutes until deep golden and crispy. Drain on paper towels, then chop into 1 cm pieces. KEEP 3 tbsp bacon fat in a bowl.

Lower oven to 190°C/375°F. Butter a deep 9×13-inch (23×33 cm) ceramic or glass baking dish generously.

Bring 7 quarts water to a rolling boil. Salt aggressively (3 tbsp).

While water heats, cook mushrooms: heat the largest sauté pan over high. Add reserved 3 tbsp bacon fat + 30 g butter. When smoking hot, add ALL mushrooms in one layer (two batches if needed). Cook undisturbed 5 minutes until golden underneath. Toss, cook another 5 minutes until deeply browned and liquid gone. Add garlic in last 60 seconds. Season and set aside.

Drop penne into boiling water. Cook exactly 6 minutes (3 minutes less than package). Reserve 1½ cups pasta water, then drain.

In the same mushroom pan, melt remaining 50 g butter over medium. Whisk in 3 tbsp flour (optional for thicker sauce) and cook 90 seconds. Slowly whisk in cream + milk. Bring to simmer, then remove from heat.

Off heat, stir in 100 g Parmesan, 80 g Pecorino, nutmeg, 1 tsp salt, and lots of pepper. Add ½ cup pasta water to loosen. Taste — it should be highly seasoned.

In the largest bowl you own, combine undercooked penne, mushrooms, chopped bacon, cream sauce, half the mozzarella (150 g), and another ½ cup pasta water. Mix gently but thoroughly. Sauce will look loose — perfect, it thickens in oven.

Transfer to buttered baking dish. Top with remaining 150 g mozzarella, 50 g Parmesan, and butter-toasted panko. Cover loosely with foil (spray inside with oil so cheese doesn’t stick). Bake 25 minutes. Remove foil, bake another 10–12 minutes until deep golden and bubbling at edges.

Rest 15 full minutes (hardest step!). Sprinkle with parsley, crack extra pepper, and serve with a big salad and red wine. Prepare for total silence followed by “can you make this every week?”