I read a book in which at least 2 people, a man & a woman, went back to late medieval Europe - Germany, I think. The woman landed on a road between villages & was picked up by a small town baker's son, also a baker, looking for a village where he could set up a baking business. They became business partners, she had coffee beans imported to go with his pastries, and things went so well, she decided to stay in that time period. I don't remember anything about the male time traveler & what he did.
Ring any bells?