Add the butter, milk, and cream to a medium size pot, and heat over very low heat. Keep warm.

Next, add the bacon to a large rondeau pot or frying pan over medium heat and cook until very crispy and browned, which takes about 5 to 6 minutes.

Remove the bacon from the pan and set aside, and then add the leeks to the pan and cook them in the rendered bacon fat for 3 to 4 minutes.

Add in the cabbage, season with salt, and cook over medium-low heat for 6-7 minutes or until very tender. Keep warm.

Boil the potatoes in a large pot of boiling salted water for 5-7 minutes or until tender. They should cook in that amount of time if you thinly slice them.

Before removing the potatoes, quickly mix in the green onions with the warm milk and butter mixture just to heat them up.

Strain the potatoes completely and then mash them through a food mill.

Fold in the butter-milk and green onion mixture until combined and then fold in the cabbage, bacon, salt, and pepper until combined. Serve.