Boil a large pot of water, salt generously, and cook pasta to al dente, according to package directions. When the pasta is tender, scoop out about 1/2 cup of the water; drain the rest and set pasta aside.
Meanwhile, melt 1 tablespoon butter in a large skillet over medium heat. Add red pepper flakes and 1 clove of the minced garlic. Cook for 30-60 seconds, just until fragrant. Stir in the breadcrumbs and cook until golden, 1-2 minutes. Transfer breadcrumbs to a bowl or plate, wipe out the skillet, and return it to medium heat.
Melt another 2 tablespoons of the butter, then add mushrooms and oregano to the skillet. Cook for 3-4 minutes, stirring occasionally, until mushrooms are tender and browned. Season with salt and pepper, add remaining 3 cloves of minced garlic, and cook for 1 minute.
Reduce heat to medium-low and add the remaining 2 tablespoons butter, drained spaghetti, Parmesan, salt, and pepper. Toss well and add reserved pasta water, a little at a time, until the sauce is loosened to your desired consistency.
Taste pasta and season with extra salt and pepper, as desired. Divide into portions and sprinkle with breadcrumbs, fresh parsley or oregano, and more Parmesan, as desired. Serve immediately.
Last step!Please leave a review and rating letting us know how you liked the recipe. This helps my small business thrive and continue providing free recipes and high-quality content for you.
Notes
Leftovers: keep well, tightly-covered, for 3-4 days in the fridge. For best results store, the breadcrumbs separately, so they don't absorb any moisture from the pasta, mushrooms, or sauce until you're ready to reheat and eat.
Nutritional info: is an estimate based on dividing the recipe as written into 4 servings. Depending on how hungry your crowd is, and how many sides you serve, you may find this yield varies.