Preheat oven to 350 degrees. Line an 8×8 square baking pan with parchment paper and set aside.
Add flour, sugar, salt & cubed butter to bowl of a food processor and pulse until combined. Mixture will be very crumbly. Take 1 cup of mixture and set aside. Press remaining mixture into the bottom of your prepared baking pan. Bake for 15 minutes.
While crust is baking, whisk eggs in a large bowl. Add in sugar, sour cream, flour, salt, lemon juice and zest. Whisk to combine. Gently fold in berries.
Remove crust from oven and spoon berry filling over hot crust. Sprinkle top of berry filling with reserved crust mixture. Bake for another 45 minutes -1 hour or until top is lightly browned.
Cool completely and refrigerate for 2 hours before serving. Cut into squares and serve.