Rinse the strawberries, hull them, and slice them thinly. Put them in a bowl and sprinkle with 1/3 cup of sugar. Let them stand at room temperature while you prepare the biscuits. Stir occasionally.

Combine the flour, baking powder, sugar, and salt in a large bowl; whisk to blend the dry ingredients thoroughly.

Add the heavy cream and vanilla and mix until a soft dough is formed.

Turn the dough out onto a lightly floured surface and shape it into a circle or square about 1 to 1 1/4 inches thick.

Cut the dough into 8 wedges or squares and place them on the parchment paper-lined baking sheet.

Heat the oven to 400 F.

Place the baking sheet in the freezer while the oven preheats.

Combine the remaining 1 tablespoon of cream and 1/2 teaspoon of vanilla in a small bowl and set aside.

Bake the biscuit wedges for 12 minutes, then brush them with the cream and vanilla.

Sprinkle the cream-topped biscuits with the sparkling sugar and return them to the oven. Bake until they are lightly browned, 3 to 6 minutes longer.

Make the whipped cream while the biscuits cool.

Put the 1 cup of heavy whipping cream in a bowl with the confectioners' sugar and 1 teaspoon of vanilla and beat with the whisk attachment of an electric mixer until soft peaks develop. The peaks should curl over slightly. Avoid overbeating.

To assemble the strawberry shortcakes, split a biscuit horizontally and fill it with strawberries and a spoonful of whipped cream. Spoon another dollop of whipped cream over the top of the biscuit and place a few strawberry slices on it.