Mix the mashed potato and turnip together in a large bowl.
In a large pan, heat the vegan butter over medium-high heat. Add the cabbage, mix well, and cook until wilted, about 5 minutes. Then mix in the kale and cook for another 2 minutes.
Mix the cabbage and kale mixture into the potato and turnip mixture. Stir in the melty vegan cheese here, and taste to adjust for salt and pepper.
Turn the whole mixture out into a greased 9 x 13" casserole dish. Sprinkle the top with vegan parmesan. Cover with aluminum foil and bake at 350F for about 30 minutes, then 5 more minutes uncovered – until it is warmed through and a bit crispy on top.
Enjoy hot on its own, or with gravy, tofu, or any other dish you are making for dinner.