This is an excerpt from Koge Bog
(Denmark, 1616 - Martin Forest, trans.)
The original source can be found at Martin Forest's website
VI - To cook cabbage. There is no need to write much about it, every farmer's wife knows how. And often at a farmer's you will taste a better cabbage than in the noble's kitchen. However this is how a cabbage is cooked: Put water and oats on the fire with a red onion or two finely chopped. Let it seethe until it is nice and smooth. Chop the cabbage finely, the finer the better it will be. When the sauce is smooth then put the cabbage into it and let it seethe until it is soft. Then put butter in: but if you want it with lard then grind the lard finely first and let it seethe with the oats.