Instructions

• Preheat the oven to 350 °F. Grease a 9x9-inch square baking dish.
• To make the crust, combine the sugar, flour, salt, and butter in an electric mixer fitted with a paddle attachment. Beat the ingredients on medium speed until the mixture looks dry and crumbly.
• Reserve 1 ½ cups of the crust mixture to use as a topping. Press the remaining mixture into the bottom of the pan. Bake the crust for 12 to 15 minutes, until golden brown.
• While crust is cooling, prepare the filling. Whisk the eggs in a large bowl and add the sugar, sour cream, flour, lime juice and zest, and salt. Fold in the blackberries.
• Spread the mixture over the crust. Sprinkle the reserved crust mixture over the filling.
• Bake for 45 to 55 minutes, until the top is lightly browned. Cool for 1 hour before slicing and serving.