NYT Cooking: Clafoutis, as you may must know by now, are among my favorite vehicles for seasonal fruit. I love the way blueberries and blackberries bleed into the batter as this bakes. Let it cool for about a half- hour, or completely, before you serve it, and be careful when you cut into it, as the berries can splatter when they’re warm. My clafoutis are not very sweet, and%...