Preheat the oven to 375ºF. Generously butter the bottom and sides of a 12-inch (30-cm) oval casserole.
Add the milk, 1/3 cup (65 grams) sugar, eggs, vanilla, salt, and flour to the bowl of a blender. Blend until smooth, about 1 minute.
Pour a 1/4-inch layer of batter in the prepared baking dish. Set it over a medium flame on the stove for 1 to 2 minutes, until the batter just begins to set at the bottom of the dish.
Spread the cherries into single layer in the pan. Pour the remaining batter over them.
Sprinkle the remaining sugar on top.
Bake for one hour, until the flan puffs up, and is deeply golden.
Let the clafoutis cool 10 to 15 minutes, and dust with confectioners' sugar, if desired, before serving. May also be served at room temperature.