Heat the olive oil in a wide deep sauté pan. Add the onion and cook until translucent. Add the chard and cook until completely wilted. Drain the chard mixture, then chop it fine and squeeze dry. Combine the chard mixture, ricotta, and cumin. Season to taste with salt and pepper.
Roll, fill, and cut the ravioli as directed on, using
Heat a large pot of salted water to boiling. Drop in the ravioli and simmer about 4 minutes. Remove them with a slotted spoon or large skimmer. Shake off the excess water and place on serving plates. Drizzle with the melted butter and sprinkle with Parmesan. Serve hot.