Although three pounds of cabbage sounds like a lot, it cooks down a tremendous amount. If you wish, you can add a teaspoon or two of caraway seed to the cabbage during the last 20 minutes of cooking. Though my family did not do that, it is not unusual to do so.
Slice each quarter crosswise into ½ inch wide ribbons.
In a heavy-bottomed pot large enough to hold the cabbage comfortably melt four tablespoons of the butter.
Sauté the onion in the butter until golden.
Add the cabbage. Season generously with salt and pepper.
Sauté on medium heat, stirring often, until the cabbage wilts.
Reduce the heat if the cabbage starts to stick to the pot.
Continue to cook on medium low, partially covered and stirring often, until the cabbage is silky, golden, and sweet. This will take 1 ½ to 2 hours total from start to finish.
The cabbage can be cooked several hours in advance to this point. Warm the cabbage before proceeding.
Bring 3 quarts of water to a rolling boil. Add 1/3 cup of salt.
Cook the egg noodles in the salted water until just done. They should be slightly toothy and definitely not mushy.
Drain the noodles.
Add the noodles to the cooked cabbage along with the remaining 2 tablespoons of butter. Toss well.