In a large bowl, sift together flour, 3 tablespoons sugar, baking powder, and salt. Using a pastry cutter or two knives, cut in butter until the largest pieces are the size of small peas. Stir in blueberries and zest. Using a fork, whisk together cream and egg in a liquid measuring cup. Make a well in the center of the dry ingredients, and pour in cream mixture. Stir lightly with fork just until dough comes together. Turn out onto a lightly floured surface, and knead a few times to mix well. (Be careful not to over mix or over knead) Pat dough into a 6 inch square, cut into four 3 inch squares. Cut each square in half on the diagonal to make 8 triangles. Transfer to a cookie sheet sprayed with Pam. Brush tops with cream, and sprinkle with sugar. Bake until golden brown, 20-22 minutes at 400 degrees.