Instructions

Process flour and salt in food processor until combined, about 3 seconds. Scatter butter over top and pulse until mixture resembles coarse crumbs, about 10 pulses. Transfer to bowl. Sprinkle 6 tablespoons ice water over mixture. Using rubber spatula, stir and press dough until it sticks together, adding up to 1 tablespoon more ice water if it will not come together.
Turn dough onto lightly floured counter, form into 4-inch disk, wrap tightly in plastic wrap, and refrigerate for 1 hour. (Wrapped dough can be refrigerated for up to 2 days or frozen for up to 1 month.)
Adjust oven rack to lower-middle position and heat oven to 375 degrees. Line rimmed baking sheet with parchment paper. Let chilled dough sit on counter to soften slightly, about 10 minutes, before rolling. Roll dough into 12-inch circle on lightly floured counter, then transfer to prepared sheet.
Gently toss apricots, blueberries, and 5 tablespoons sugar together in bowl. Mound fruit in center of dough, leaving 2-inch border around edge. Carefully grasp 1 edge of dough and fold up 2 inches over fruit. Repeat around circumference of tart, overlapping dough every 2 inches; gently pinch pleated dough to secure, but do not press dough into fruit.
Brush dough with remaining 1 tablespoon water and sprinkle remaining 1 tablespoon sugar evenly over dough and fruit. Bake until crust is deep golden brown and fruit is bubbling, 45 to 50 minutes. Transfer sheet to wire rack and let tart cool for 10 minutes. Using metal spatula, loosen tart from parchment and carefully slide onto wire rack; let cool until warm, about 30 minutes. Cut into wedges and serve.