Cook bucatini in salted water; reserve 1 cup of pasta water.
Heat olive oil in a skillet. Sear steak until golden, then set aside.
In the same skillet, melt butter. Add garlic and cook shrimp for 2–3 minutes.
Add Calabrian chili oil and lemon juice to the pan. Stir and thicken.
Return steak and shrimp to the skillet. Add cooked bucatini and toss.
Add a splash of pasta water to create a glossy sauce. Season with salt and pepper. Garnish with herbs. Serve hot.
