Preheat your oven to 375°F (190°C). While the oven is heating, butter a 9-inch baking dish. Arrange the sliced peaches evenly in the bottom of the prepared dish.
In a blender or a mixing bowl, combine the flour, sugar, and salt. If using a bowl, whisk the dry ingredients together until there are no clumps.
Pour in the milk, eggs, and vanilla extract. If you're using a blender, blend until smooth. If you're using a bowl, whisk until the batter is smooth and well combined. A few small lumps are okay!
Pour the batter evenly over the peaches in the baking dish. Drizzle the melted butter over the top of the batter. This will help the clafoutis brown nicely.
Bake in the preheated oven for 45-50 minutes, or until the clafoutis is puffed up and golden brown. A knife inserted into the center should come out clean.
Let the Peach Clafoutis cool slightly before serving. It will deflate a bit as it cools, which is perfectly normal. Dust with powdered sugar, if desired, and enjoy!