Make sure you read the cooking notes before you start.
Preheat the oven to 350°F. Butter generously a 8-9 inch circular pie dish or skillet (or 8 individual 1-cup baking dishes or ramequins).
In a large mixing bowl, whisk together the milk, sugar, eggs, vanilla, Kirsch (optional). Add the flour and salt, and whisk until smooth.
Place the cherries at the bottom of the prepared dish (or a handful at the bottom of each individual dish). Pour batter over top.
Bake for 1 hour (or 40 minutes for individual clafoutis). The clafoutis is done when puffed and brown on the edges, and a knife plunged in the center comes out clean.
Transfer to a cooling rack. The clafoutis will deflate as it cools.
Sprinkle with powdered sugar, and serve warm.
