Preheat oven to 350' F and lightly butter a 9" heavy pie plate. (I use a Pyrex glass pie plate)
In blender add eggs, milk, sugar, vanilla, nutmeg and salt and blend well for 30-60 seconds.
Add flour and blend again until smooth, 60 seconds, then pour into greased pie plate.
Arrange the sliced plums over the top and bake in oven until it's lightly browned on the edges and has a slight jiggle in the middle, approximately 40-35 minutes.
Let cool slightly and serve warm, sprinkled with confectioners sugar.If serving later, rewarm slightly before serving.
Notes
The proper consistency is like a clafoutis which is in between a cake and a custard. It is best achieved by not over cooking.