Cook the ravioli. If using store-bought ravioli, follow the package instructions to cook them. Bring a pot of salted water to boil. Turn down the heat so the water only gently simmers, and then add the ravioli. The key is simmering the water (not boiling it hard) so they don’t break. For the fresh ravioli depicted in this article, it takes only 3 minutes of gentle simmering for them to be ready. Drain them, but reserve 1 tablespoon of the water.
To a bowl or pot large enough to hold the ravioli, add the pesto, one tablespoon of the reserved pasta water, lemon zest, one tablespoon of lemon juice, a pinch of salt, and a pinch of black pepper. Mix the pesto sauce, and then gently add the ravioli. Fold them gently into the sauce so they don’t break.
Plate the ravioli and top with freshly grated parmesan and chili flakes/red pepper flakes (optional). It helps to use a silicone spatula to get all the sauce from the serving bowl into the individual bowls.
