Steam the carrot slices until crisp-tender. Heat the oil in a large pan and add the onions, cooking for a few minutes. Then add cabbage and cook for 10 minutes more. Remove from heat and stir in the salt, pepper, and carrots. Oil an 8" x 8" baking pan. Mix half the tofu sour cream into the vegies. Add the nutritional yeast to the remaining tofu. Put this on top of the vegetables. Mix crumbs and seeds and sprinkle on top of the casserole. Bake at 350 for 35-40 minutes until top is lightly browned.
For Tofu Sour Cream: Blend all ingredients together until creamy and smooth.