About 8 at a time, lower the ravioli into the oil on a slotted spoon and fry for 1-2 minutes, turning until golden and puffed. Lift the fried ravioli onto the paper-lined tray to drain, and continue frying in batches until they are all done. Drain the last batch on the paper – and use more paper to pat the tops so they’re really dry. Tip the hot ravioli onto a big plate or platter and drizzle with the truffle oil, then quickly sprinkle with the grated parmesan and carefully toss to coat. Some of the ravioli will still be piping hot, so be careful with this bit.