Heat oven to 425°F. In large bowl, mix 3/4 cup sugar and the cornstarch. Add blueberries and lemon juice; mix well. Spoon into ungreased 8-inch square (2-quart) glass baking dish.
Knead dough until softened and no longer crumbly. Flatten into a round; place between 2 sheets of cooking parchment or waxed paper. Roll into 10-inch square. Carefully peel off top sheet of paper. With pizza cutter or knife, cut dough into 5 rows by 5 rows. Replace paper; carefully turn dough over, and remove second sheet of paper.
Using small offset spatula, place individual dough pieces over blueberry mixture, overlapping pieces and covering entire top. Sprinkle with 1/2 teaspoon sugar.
Bake uncovered 25 to 30 minutes or until crust is golden brown. Cool 20 minutes before serving.