Lotus root soup can be made in both a pressure cooker and a wok aromatic pot. When it comes to stewing lotus root, using a pressure cooker saves cooking time over a casserole. A casserole takes about three hours to cook lotus root while a pressure cooker only takes between thirty and forty minutes. When cooking in a casserole, use high heat and then turn the heat down to a low simmer so that the lotus root is more flavorful and retains its crunchy texture.