By dark ages, when do you mean? A lot changed in the life of peasants between 500 and 1500 CE: significant technological innovations in farming, food production and preservation; the developing sophistication and breadth of merchant trading further changed the nature of available goods through the latter middle ages.

By winter, where do you mean? Variable geography determines 'winter climate' which results in different preparation habits and measures: compare England to Provençe, for example.

hi! you're specifically asking about preparation, but you may find these posts of incidental interest. They don't address preparation directly (although there are a couple of mentions), but may help paint a picture of wintertime life

• What did commoners in agrarian societies do during the winter?

• What did people in Scandinavia and other cold climates do during the winter months before modern technologies were available?

• What was the average number of holidays per year during the Middle Ages? / What did a peasant do during the winter?

• What did medieval rural peasants do all winter in northern Europe?

• How have people in far northern countries coped with lack of exercise in harsh winters?

• Winter in ancient times

• How much did a medieval European peasant work?

• What did peasants do during the winter?