Bring a large pot of generously salted water to a boil.
In a frying pan over medium heat, add the pancetta in a single layer. Fry undisturbed until the pancetta starts to brown on one side and some fat beings to render out.
Once the pancetta is browned on one side, start stirring it, continuing to fry until it's cooked through and there is a tablespoon or two of rendered fat in the pan. Don't overfry it, otherwise it will end up chewy. Transfer the pancetta to a bowl, leaving as much fat in the pan as possible.
Once the water is boiling, add the pasta and cook for 8 minutes (or whatever the package directions say).
Add the onions to the pan and fry until they're starting to brown.
Add the grapes and continue frying until the grapes are cooked through and starting to caramelize.
When the pasta is done, reserve some of the boiling liquid from the pasta and then drain the pasta.
Add the pasta to the pan with the pancetta and grapes and toss to distribute evenly. Add the gorgonzola, basil and a bit of the reserved pasta water and toss until the cheese is mostly melted and forms a sauce. If your pasta is sticking together, add a bit more pasta water.