How do I cook bolognese-filled ravioli from frozen?
The recipe does say to cook them in the sauce if frozen, but I think it is more a suggestion about another method you could use to cook the ravioli. You could definitely still just boil the frozen ravioli and add them to the sauce. I would probably boil them an additional minute or two being very careful to check to see if they are done past the 4 minute mark. Typically I'd say if the ravioli float, they are done, but the bolognese sauce filling may be too heavy to allow the ravioli to float.

To cook them directly in the sauce, I would heat the sauce up and then add the ravioli so that they make a single layer and can be nestled into the sauce. I would probably cook them 6-7 minutes from the time the sauce comes back to a simmer, but once again, I'd be very careful to watch them. Ravioli is usually pretty easy to tell if it is done and since it will be in the sauce you can easily poke one in the pan, you shouldn't have trouble getting it right.

EDIT: I would actually not recommend refrigerating this recipe rather than freezing it because the sauce filling could make the pasta soggy unlike a cheese filling.