Preheat oven to 400°F. Lightly butter a baking pan (or line pan with parchment paper.)
Combine flour, ½ cup sugar, cocoa, baking powder, baking soda and salt in a 2 quart mixing bowl. Cut in butter until mixture resembles coarse crumbs.
Combine ½ cup buttermilk, and egg. Stir buttermilk mixture into flour/butter mixture; mix until dry ingredients are moistened.
Gather dough into a ball and knead against the sides and bottom of the mixing bowl. Transfer dough to a lightly floured surface and pat or roll to ¾-inch thickness. Cut out rounds with 3-inch biscuit cutter. Place rounds on prepared baking sheet, 1-inch apart, brush with buttermilk and sprinkle with sugar. Bake 12-15 minutes or until done.
Hull and slice strawberries. Combine berries, sugar and balsamic vinegar; let stand at room temperature for about 30 minutes, stirring occasionally. (Refrigerate if preparing ahead of time.)
Add water to small heatproof cup and sprinkle gelatin on top. Allow gelatin to soften 5 minutes. Place cup in pan of simmering water and heat until gelatin dissolves then let cool to room temperature.
In a cold mixing bowl, whip cream. As it begins to thicken beat in gelatin mixture and gradually add sugar; beat constantly until mixture forms stiff peaks. Refrigerate until ready to assemble dessert.
Assembly: Cut shortcakes horizontally in half. Place bottom portions cut side up on individual dessert plates, spoon on half of the berries, cover with top of shortcake, spoon on additional berries and top with a dollop of whipped cream. Drizzle juices from berries around shortcakes.
Adding gelatin stabilizes the whipped cream and allows it to hold up longer.