Cook the potatoes until fork tender. I like to use a thermometer and get them to an internal temp of 200 F / 93 C. These days I microwave them on high for about 8 - 10 minutes, flipping halfway through. But feel free to boil them or whatever method you like.
To microwave, wash and dry the potatoes. Poke a few holes in the potatoes with a fork or knife.Add them to a microwave safe dish and microwave on high for 4 - 5 minutes. Flip them and then cook for another 4 - 5 minutes or until they reach an internal temp of 200 F / 93 C.
Cut them in half lengthwise once they are cooked through, and let them cool down for a few minutes. Cut each half in half again longways, and carefully peel back the skin. It should come off easily.
Heat up the vegan butter and plant milk in a microwave or on the stovetop until the mixture is melted and hot (but not boiling hot).
Mash the potatoes in a bowl with a potato masher, or a potato ricer. Pour over the milk and butter mixture, season with salt, garlic powder and nutritional yeast. Optionally, fold in about 1/2 cup of your favorite shredded vegan cheese.
The mixture should be on the dryer side, this will help it keep it's shape and not get too mushy.
Scoop about 2 Tbsp (35g) of the mixture and shape into an egg like shape. Or use an egg mold if you have one. Add them to a baking sheet and freeze for about 1 hour or until firm enough to handle without altering their shape.