Preheat oven to 400 degrees. Line a baking sheet with a Silpat or parchment paper; set aside.
Sift flour, sugar, baking powder and salt into a large bowl. Using a pastry blender or 2 knives, cut in butter until the largest pieces are the size of small peas.
Using a fork, whisk together the cream, lemon zest, lemon juice and eggs in a large glass measuring cup. Make a well in the center of flour mixture, and pour in cream mixture. Stir lightly with fork just until the dough comes together (do not over-mix), and gather into a rough, shaggy ball.
Set the rough ball in the center of the prepared baking sheet and pat it gently into a round about 1 inch thick and 7 inches in diameter.
With a sharp knife or a pastry scraper, cut the round into eight wedges; separate the wedges. Brush the scones with additional heavy cream and sprinkle with additional sugar. Bake until the scones are deep golden and a toothpick inserted into the center of a wedge comes out clean, about 18 to 22 minutes. Let the scones cool for 10 minutes before serving. Serve with blueberry preserves on the side.