Cook the spaghetti in salted water until al dente. Drain. Note that you have to be generous with the amount of salt you add to the water. The sauce is very light so the pasta itself has to be well seasoned.
While the pasta cooks, make the sauce.
Finely slice the bacon.
Heat a pan. Add the bacon. Cook until browned. If you’re scared of bacon fat (I’m not — it’s so full of flavors), or if there’s too much bacon fat (i.e., more than a tablespoonful), pour all or some of it off. Otherwise not, leave it there.
Add the butter and olive oil.
Throw in the cooked spaghetti. Toss to coat every strand of pasta with oil.
Add the ricotta and parsley.
Season with salt and pepper.
Toss to distribute the bacon and ricotta well.
And that’s it! You’re ready to serve and enjoy your spaghetti with bacon and ricotta.