Blackberry Streusel Tart Recipe

Ingredients

• 1 1/2 pints blackberries
• 1/2 cup granulated sugar
• 1 tablespoon cornstarch or tapioca flour
• 1/2 teaspoon freshly squeezed lemon juice
• 1 9 1/2-inch tart crust
• 3/4 cup all-purpose flour
• 1/3 cup firmly packed brown sugar
• Pinch of kosher salt
• 3 ounces cold unsalted butter, cut into 1/2-inch pieces
• 1 recipe Chantilly cream (see below)