If you love stuffed shells, you'll love this recipe for Mushroom Kale Stuffed Shells! The ultimate Italian comfort food! The key to adding the vegetables to the ricotta filling is draining them VERY WELL. If they’re the slightest bit wet, they’re going to loosen the filling and impact the overall dish. I squeeze the liquid out of the kale, then dab it and the mushrooms with paper towels to soak up any excess moisture before adding them to the cheese mixture.