Cook the pasta according to the package directions. When done, drain the water out, and return the pasta to the pot. Pour the olive oil over the top and toss to coat.
Cook the bacon and onios:
In a large pan, cook the bacon pieces over medium-high heat for about 3 minutes, stirring. When it begins to brown and crisp up, add the onions, garlic (or garlic powder), and red pepper flakes. Continue cooking until the onions are soft and golden, for about 5 minutes.
Combine & serve:
Transfer the cooked bacon and onions into the pot with the spaghetti, add the Parmesan cheese, and toss to combine.
Serve this bacon spaghetti pasta topped with additional Parmesan cheese.