Cream together butter, sugar, eggs, and vanilla. Add grist mill flour, baking powder and milk. Makes a stiff batter.
Spread into 9x13 inch greased pan. Place plums, cut side up, on batter. Sprinkle with topping (rub butter, flour and sugar until crumbly).
Bake at 350ºF for 40 minutes. Serve warm with whipped cream or ice cream. Freezes well.
Notes
This recipe comes from a fantastic cookbook prepared by the Friends of the Grist Mill in 2003 based on some of the most popular recipes in the Tea Room.