Blackberry-Basil Tart

Stir together sour cream and 3/4 cup sugar. Scrape in vanilla bean seeds; stir to combine. Discard pod. Refrigerate filling, covered, until firm, about 3 hours or up to 2 days, before using.

Preheat oven to 375 degrees. Press dough into a 13 3/4-by-4 1/4-by-1-inch oblong tart pan with a removable bottom. Trim edges of dough flush with pan. Refrigerate until firm, about 30 minutes. Bake until golden and crisp, about 18 minutes. Let cool completely on a wire rack.

Stir together blackberries, remaining 3 tablespoons sugar, 1 tablespoon water, basil, and cinnamon in a small saucepan over medium heat. Cook, stirring gently, until berries have softened and released their juices and mixture is warmed through, about 2 minutes.

Spoon sour cream filling into tart shell. Top with the berry mixture. Garnish with basil sprigs.