Boil peeled, chopped potatoes in a medium pot - you don't need to measure out water, just make sure your water covers over your potatoes. Be sure to cut potatoes into large chunks to help them cook faster. You can also skip this step and use frozen peeled potatoes and microwave or boil until soft.
Add a pinch of salt to the water, and bring to a boil.
When potatoes are soft enough to be easily pierced with a fork, they are done. Drain in a colander, let sit for a moment while melting butter.
Add butter to a pan and heat until light and foamy. Stir in greens, and let wilt and cook down, stirring to prevent burning.
Add green onions and cook an additional minute.
Pour in milk slowly, stirring as you pour it in, and mix well. Reduce heat to medium.
Add in potatoes, and use a masher or a hand mixer to start mixing potatoes and mash them with greens, don't overwork potatoes but mash to soft.
Season with salt and pepper to taste - I like to add a bit of garlic powder too sometimes, though it is not strictly traditional.
Add a pat of butter in the center when serving, and a crack of fresh pepper on top!