Mix first 7 ingredients in bowl. Rub in butter until mixture resembles coarse meal. Add cream; stir with fork until clumps form. Gather dough into ball. Wrap in plastic; chill one hour.
Preheat oven to 350°F. Line large baking sheet with parchment. Roll out dough on floured surface to 3/4-inch thickness. Using floured 3-inch diameter cookie cutter, cut out rounds. Place on baking sheet. Reroll scraps; cut out additional rounds for 6 rounds total. Brush with glaze. Bake until shortcakes are golden, about 30 minutes. Transfer to rack and cool.
Combine strawberries and 6 tablespoons sugar in large bowl. Transfer half of berry mixture to another bowl. Using fork, crush berries in 1 bowl to chunky sauce consistency. Let both bowls stand at room temperature until juices form. Cut shortcakes in half. Place 1 bottom half in each of 6 bowls. Spoon some crushed berries over each, then top with generous amount of sliced berries. Cover with shortcake tops. Dust with powdered sugar.
