Preheat the oven to 375 degrees F. Combine the first 5 ingredients in a bowl. Cut in the cold butter until the mixture is crumbly. Add milk and stir just until the dough holds together. Transfer the dough to a lightly floured surface and shape into a ball. Press the dough into a 1" thick circle. Cut the dough into six, 2 3/4" rounds and set on a parchment paper-lined baking sheet. Brush shortcakes with melted butter; sprinkle with granulated sugar. Bake 18 to 20 minutes, or until puffed and golden. Cool to room temperature.
Cut shortcakes in half. Divide and top bottom halves with whipped cream. Top whipped cream with raspberries, saving 12 to garnish the top. Set on the top half of each shortcake. Set 2 raspberries on each shortcake, dust with icing sugar, garnish with mint, and serve.