Combine strawberries, 1/2 cup sugar, and, if desired, almond extract. Cover berry mixture, and let stand 2 hours.
Beat whipping cream at medium speed with an electric mixer until foamy; gradually add 2 Tbsp. sugar, beating until soft peaks form. Cover and chill up to 2 hours.
Combine flour, remaining 1/4 cup sugar, and baking powder in a large bowl; cut butter into flour mixture with a pastry blender or two forks until crumbly.
Whisk together eggs, sour cream, and vanilla until blended; add to flour mixture, stirring just until dry ingredients are moistened. Drop dough by lightly greased 1/3 cupfuls onto a lightly greased baking sheet. (Coat cup with vegetable cooking spray after each drop.)
Bake at 450° for 12 to 15 minutes or until golden.
Split shortcakes in half horizontally. Stir together strawberry jam and 2 Tbsp. chopped fresh mint. Spread cut sides of bottom shortcake halves evenly with jam mixture. Spoon about 1/2 cup berry mixture onto each shortcake bottom; top each with a rounded Tbsp. chilled whipped cream, and cover with tops. Serve with remaining whipped cream. Garnish, if desired.