1. Preheat oven to 400 degrees Fahrenheit.
2. Mix flour, baking powder, salt, and sugar in a large bowl. Add butter, crumbling the mixture with your fingers to form coarse crumbs. Gently toss in the blueberries.
3. Make a well in the center of the crumbs and pour in the heavy cream. Mix.
4. Remove the dough from the bowl and place on a lightly floured surface. Form the dough into a long rectangle.
5. Using a knife, cut triangles from the dough and place on prepared baking sheet.
6. Brush the top of the scones with heavy cream and sprinkle lightly with coarse sugar. Bake for 15 to 20 minutes, until golden. Serve with jam.