What was the condition that Jacobs grandmother had to work under in order to bake her nice crackers at midnight

The thing in this story is that her nice crackers became so famous in the neighborhood that many people were desirous of obtaining them. Because of numerous requests of this kind, she asked permission of her mistress to bake crackers at night, after all the household work was done; and she obtained leave to do it, provided she would clothe herself and her children from the profits. After proposing these terms, after working hard all day for her mistress, she began her midnight bakings, assisted by her two oldest children.