Make the tart crust by mixing together sugar, flour, salt and butter. Mix until it forms a dough.
Press the dough into a 9 inch tart pan making sure to go up the sides. Bake the crust at 400*F for 15 minutes.
While the crust is cooking, mix the fresh blackberries with flour, sugar, and lemon juice.
Remove the crust from the oven and spoon the blackberry mixture into the pre baked crust. Set the temperature to 350*F and bake for 30 minutes.
Remove from the oven and cool. Enjoy with whipped topping, vanilla ice cream or plain. ENJOY!