In folklore, offerings for a brownie were usually left by the hearth.
The brownie was a household spirit in Scottish and northern English tradition, believed to work at night while the family slept. It might sweep floors, wash dishes, churn butter, or help with farm work. In return, householders left food or dairy offerings, commonly a bowl of milk or cream, porridge, or a small cake.
The hearth was more than a fireplace: it was the symbolic and practical centre of the home. Older traditions connected household spirits and ancestral guardians with this place, so the hearth became the natural location for feeding a brownie. A doorway, window, or staircase might feature in other supernatural tales, but those are not the standard answer here.
Brownies were also thought to be easily offended. Giving one clothing, treating it badly, or taking its work for granted could make it disappear permanently. Their folklore later influenced children’s literature and the Brownies section of Guiding.