In a bowl, toss the raspberries with 1 tablespoon of the sugar and refrigerate until ready to serve.
Preheat the oven to 400 degrees F. In a mixer fitted with a paddle attachment, mix the flour, salt, the remaining 1 tablespoon of sugar, baking powder, and lemon zest. Mix in the whipped cream until the mixture is moistened and just forms a ball. Turn out onto a lightly floured work surface and knead briefly just to bring the dough together.
Form the dough into a log then use a rolling pin to roll it out into a long rectangle about 1-inch thick and 3 inches wide. Making diagonal strokes with a sharp knife, cut into 4 or 6 large triangular biscuits. Arrange on a sheet pan and bake until golden brown, about 20 minutes. Let cool on a wire rack.
When ready to serve, split the biscuits in half horizontally. Place the bottoms on serving plates. On each, place a spoonful of raspberries with the syrup that has collected in the bowl, a dollop of sour cream, and a sprinkling of brown sugar. Place the top halves of the biscuits on top. Serve immediately.