Dear Cheri
I small potato or a 1/3 cup of mashed potato is one carb portion so that means you can have it but count it as a carb not a vege!! And lose the butter!! If you have to make it mushy use a splash of low fat milk, or I like hommus in mine. Or add to it some Beans, chick peas, lentils, herbs (like parsley or fresh coriander) to make it interesting. A bit of olive oil would even be better than the butter.
The other think i do and I am not sure if they have this in the US is shepherd's pie, so you make up some savory beef mince with diced onion, capsicum, garlic, cumin, chopped tomatoes, a bit of red wine (like an italian style sauce) and then put it in a dish and then mash the potato up and spread it over the top, sprinkle a little cheese and paprika over the top and bake until the cheese melts and it's great. Last forever, the whole family will like it, You only need a little and it goes down well as a meal in itself regardless of what stage you are at, or add a salad to it.