How to Make It
Preheat the oven to 400°F. In a medium bowl, toss plums in 1/2 cup of sugar and the salt. Set aside, and let sit until needed.
Put the butter in a 2-quart baking dish and place it in the oven to melt. Whisk remaining 3/4 cup sugar, cinnamon, and milk in a medium bowl. Stir in sifted flour and gently mix just until combined.
Carefully pour the batter into baking dish once butter is fully melted. Spoon plums evenly over the top of the batter along with any juices they may have released.
Bake 40 to 50 minutes, until deep golden brown. Serve with Vanilla Ice Cream.