From 1911:
Cook the onions tender in two waters, drain them and cut them into small pieces.
Grease a pudding dish, put a thick layer of the onions in the bottom of this, strew salt and pepper over them and bits of butter.
Over these sprinkle crumbs and moisten the layer with milk.
Repeat the process, and when the dish is full make a top layer of crumbs plentifully sprinkled with little pieces of butler.
Bake covered half an hour, uncover and brown.