Preheat & Prep: Preheat your oven to 400°F (200°C). Lightly grease a 9x13-inch white ceramic casserole dish with a small dab of butter or cooking spray so the noodles don’t stick.

Prep Pasta: Break the dry spaghetti in half so it fits easily in the casserole dish. Spread the pasta out as evenly as you can in the dish; it’s okay if it overlaps and looks a little messy.

Mix Butter Sauce: In a medium bowl or large measuring cup, whisk together the melted butter, minced garlic, dried Italian seasoning (or dried parsley blend), salt, and black pepper. The mixture should look speckled with herbs and garlic.

Add Water: Carefully whisk the hot water into the butter mixture until everything is well combined. It will look like a thin, golden, herby broth.

Combine: Pour the butter mixture evenly over the dry spaghetti in the casserole dish. Use tongs or a fork to gently press the pasta down so most of it is touching the liquid. Some pieces may stick up a bit; they’ll soften as they bake.

Cover: Cover the casserole dish tightly with aluminum foil. This traps the steam so the pasta cooks through and soaks up the buttery sauce.

First Bake: Bake covered for 25 minutes. Carefully remove the foil (watch for hot steam), then use tongs to toss and separate the noodles, pulling up any strands that are clumping together and making sure they’re all getting coated in the cowboy butter.

Second Bake: Return the dish to the oven, uncovered, and bake for another 10–15 minutes, tossing once more halfway through if needed. The pasta is done when the noodles are tender, most of the liquid is absorbed, and the top looks glossy and lightly golden in spots.

Rest & Serve: Give the pasta a final toss in the dish so every strand gets coated in the buttery, garlicky herbs. Let it sit for 3–5 minutes to thicken slightly, then serve straight from the casserole dish with a big spoon, scooping up plenty of buttery sauce and herbs with each portion.