Preheat the oven to 375°F (190°C). Line a large baking sheet with parchment paper.
In a large bowl, whisk the flour, sugar, baking powder and salt together until well blended. Work the butter into the flour mixture with a pastry blender or with your fingertips until small pea-size pieces are formed. Stir in the mini chocolate chips.
In a small bowl, whisk the buttermilk and vanilla extract together. Stir this mixture into the dry ingredients just until a shaggy dough forms
Turn the dough out into a lightly floured surface. Fold the dough over into itself a few times. Do not overwork the dough! Form the dough into a 1-inch thick, 6-inch diameter round. Cut out 6 rounds with a 2 3/4-inch floured biscuit cutter. Place them about 2 inches apart on the baking sheet. (It’s important to keep the dough cold. If your kitchen is very warm, freeze the rounds for 5-10 min. before baking.)
Brush the shortcakes with heavy cream & sprinkle with coarse sugar. Bake until golden, about 17-22 minutes. Immediately transfer the shortcakes to a cooling rack. Split the cooled shortcakes and top with strawberries and whipped cream.