Preheat oven to 375 degrees. Butter ten 3/4-cup ramekins; dust with sugar. Bring milk, 2 1/2 tablespoons sugar, and salt to boil in small saucepan, stirring to dissolve sugar; remove from heat.
Melt butter in heavy medium saucepan. Add flour; stir 1 minute. Whisk in milk mixture. Cook over low heat until mixture thickens and comes to a boil, whisking until smooth. Whisk in egg yolks and Chambord. Transfer to a large bowl.
Using electric mixer with clean dry beaters, beat egg whites in another large bowl until foamy. Gradually add remaining 5 tablespoons sugar, beating until soft peaks form. Fold egg whites and 1 cup berries into milk mixture. Divide remaining 3/4 cup berries among ramekins. Spoon souffle batter over, dividing evenly. Place ramekins in a large roasting pan. Add enough water to pan to come halfway up the sides of the ramekins.
Bake souffles until puffed and gently set in centers, about 20 minutes. Sift powdered sugar over and serve with Vanilla Cream Sauce.
To make the Vanilla Cream Sauce: Whisk cream, milk, yolks, and sugar to blend in heavy medium saucepan. Scrape in seeds from vanilla bean; add bean. Stir over medium heat until custard is thick enoght to coat spoon and an instant read thermometer reads 175-180 degrees, about 8 minutes (do not boil). Pour into medium bowl, cover and chill. Can be made one day ahead. Keep chilled. Remove bean before serving.