Cook the pasta, in salted water, until al dente. Drain.
While cooking the pasta- heat a large dutch oven over medium heat, and add the oil. Once hot add the meat, salt, pepper, and onion powder. Stir everything together, breaking up as it cooks.
In a large bowl, add the milk & broth, whisking together. Set aside.
Once the meat is half cooked, add in the onion stirring to incorporate, and continue cooking the mixture until the meat's cooked through.
Scootch the meat to the side of the pot, and add the flour to the pot whisking it together with the drippings. Once evenly combined, let the mixture cook for 30-60 seconds.
Slowly pour in the milk/broth mixture, whisking to evenly incorporate. Allow the gravy to simmer until it's thickened, then remove from heat.
Return the drained pasta to it's pot. Add the butter, and stir until it's all melted and mixed in.
Serve it by adding the buttered noodles to a plate of bowl, and ladling the gravy out over top.