Actually recreating an individual meal is probably beyond the scope of our sources. As far as I am aware, nothing like a "Saturnalia dinner" menu equivalent to a "Thanksgiving" or "Christimas" dinner survives (actually, I wonder how old those concepts are...). But there is a pretty vibrant "Roman food" community, so to speak. Much of it draws on "Apicius", which was a recipe book that took its name from a famous Julio-Claudian gourmand. It is possible that the book, the current form of which is essentially Late Antique, had some basis in the historical Apicius' dinner table, but that is unknown. Regardless, it gives a sense of the flair and theatricality of Roman cooking. Bt there are other sources, such as Cato the Elder, who gives rather more practical recipes (such as a hangover cure consisting of vinegar and cabbage--I can't speak to its effectiveness).

Anyway, the best place I know of to look is the Pass the Garum webpage, which has a variety of different recipes. Around the Roman Table is somewhat less practical in its recipes but is a great book that has a lot of information on Roman dining habits.

Most important, though, is large quantities of Aglianico to authentically recreate the Roman love of Campanian wine (although Book XIV of Pliny's Natural History has an enormous amount of information about different varieties of wine and methods of preparation).