Dark Chocolate-Raspberry Clafoutis

2 3/4 cups raspberries
1 tablespoon granulated sugar
1 cup buttermilk
1/2 stick butter, melted
3 large eggs
1/2 cup packed dark brown sugar
1/3 cup all-purpose flour
2 tablespoons unsweetened cocoa powder
1/4 teaspoon salt
4 ounces dark chocolate, coarsely chopped

Heat oven to 400 degrees F. Butter 2-quart shallow baking dish.

Toss berries with granulated sugar and let stand for 15 minutes.

Blend buttermilk, butter, eggs, brown sugar, flour, cocoa and salt in blender until smooth. Scatter berries evenly in baking dish, then pour batter over top.

Bake until slightly puffed and firm to the touch - about 35 minutes. Remove from oven and immediately sprinkle with chopped dark chocolate. Cool to warm, about 20 minutes.

Serve warm or at room temperature.