Step 1Heat the oven to 350 degrees. Place the milk, one-third cup sugar, eggs, vanilla, salt and flour in the blender jar in that order. Cover and blend at top speed for 1 minute.
Step 2Pour a one-fourth-inch layer of batter in a lightly buttered, fireproof 7- to 8-cup baking dish or a 1 1/2-inch deep Pyrex pie plate. Set it over moderate heat until a film of batter has set in the bottom of the dish, about 1 to 2 minutes. Remove from heat.
Step 3Spread the cherries over the batter and sprinkle on the remaining sugar. Pour on the rest of the batter and smooth the surface with the back of a spoon.
Step 4Bake until puffed and brown and a knife inserted into the center comes out clean, about 1 hour. Sprinkle the top of the clafouti with powdered sugar just before bringing it to the table. (The clafouti need not be served hot, but it should still be warm. It will sink slightly as it cools.)