Mix flour, sugar, salt in a bowl. Cut in cold butter. Break up butter and slowly add cold water. Divide into two discs, wrap in plastic wrap, and place in fridge for 30 minutes.
Filling
Preheat the oven to 375 degrees
In a large bowl, combine apricots, blackberries, sugar, cornstarch, and lemon juice. Stir until the fruit is covered and the ingredients are combined.
Remove one disc of dough from the fridge and roll it out into a large circle. Place it on a cookie sheet lined with a parchment paper.
Pour the filling in the center and fold up the edges of the crust on top of the filling. Leave a large circle of exposed filling in the center of the galette.
Sprinkle the outer edge crust of the galette with the turbinado sugar.
Place in the preheated oven and bake for 30 minutes.
Remove and allow it to cool for 30 minutes to an hour before slicing.
Serve with a large scoop of vanilla bean ice cream.