Dietary sensitivity: This can include lactose intolerance or even just a sensitivity to different dairy products. Style of eating: Do you follow a vegan or plant-based diet and want to know about how to make a great tasting mashed potato side dish without any dairy? Out of milk: Are you craving them but out of milk and don’t want to go to the store? Lower calories or change nutritional value: You may also be looking to simply make them a bit healthier for personal reasons.
In my opinion, the best substitute for milk when making them is vegetable broth. I find it adds flavor and moisture to the mashed potatoes.
If you need to swap out both the butter and milk in mashed potatoes your best option is to use vegetable broth or the cooking liquid from the boiled potatoes in place of the milk. And then add another fat such as olive oil to the potatoes to replace the butter.