Preheat the oven to 400 degrees.
Sift together the flour, baking powder, sugar, and salt into a large mixing bowl.
Using a pastry cutter, cut the butter into the flour mixture, until it resembles small peas.
In a small bowl, mix together the yolks, milk, cream, food coloring, and vanilla. Stir it into the flour mixture just until no streaks of flour are left.
Dump the mixture onto a floured board, and pat it into a one inch thick circle. Using a floured knife, cut into eight wedges. Place them on a parchment lined baking sheet, spaced two inches apart from one another.
Brush each wedge lightly with some heavy cream and sprinkle with the sanding sugar. Bake them for 20 minutes, or until they start to lightly brown around the edges. Cool for 5 minutes on a wire rack.
Make the glaze by combining the sifted powdered sugar with the vanilla and heavy cream. Use a piping bag to apply the glaze to the scones. Serve warm or at room temperature.