Preheat oven to 180°C (350°F).
Butter and flour the tin and remove any excess. I sprinkled it with brown sugar, but I prefer flour as the base holds together better.
Sift the flour into a bowl, then add the salt, sugar and vanilla (or vanilla extract). Mix with a whisk, then add the eggs in the center.
Mix well until smooth, like a crepe batter. You can use a blender or an immersion blender.
Add the milk and cream a little at a time, stirring constantly to dilute the paste.
If you still have small lumps, strain the paste.
Pour the batter into the mould, then add the blueberries. You can start by placing the blueberries in the mould, then pouring the liquid batter over them.
Bake for around 55 minutes, or until the clafoutis is golden and set in the center. A knife blade inserted in the center should come out clean. Adjust the cooking time to suit your oven.
Important: Check cooking time after 45 min. You can open the oven without worry.
The clafoutis puffs up as it bakes, rather like a cheesecake, then falls back as it cools. It's perfectly normal.
Remove from oven and allow to cool completely if you wish to unmold. It can be enjoyed warm or at room temperature for a more melt-in-your-mouth experience.
Its texture remains perfect even after 2 days, although it firms up slightly in the fridge.
You can also serve it directly in the dish and dust it with powdered sugar if desired.