It depends on what kind of ravioli you are using. When you are using frozen ravioli, you can sauté them instead of boiling them. When you are using dry ravioli, you can not. I have seen ravioli fried in oil instead of boiling, but this can be tricky, and if it isn't done right, the pasta comes out tough, so it is not something I recommend. For this recipe, to save time and ensure the best texture, I recommend boiling the pasta.