1Heat oven to 450°F. In a large mixing bowl, combine flour, sugar, lime zest, baking powder, baking soda, and salt, stirring with a wire whisk to break up any lumps. Mix in dried pineapple; set aside.
2Grate butter through the large holes in a box grater onto a cutting board or a piece of parchment paper, and toss with dry ingredients until well combined.
3In a small bowl, whisk together 3/4 cup cream and egg; stir in lime juice. Pour cream mixture over dry ingredients, and stir just until dough comes together (it will be lumpy).
4Turn dough out onto a lightly floured surface and, with lightly floured hands, knead for about 2 minutes, then pat down into a circle. Use a rolling pin to roll dough to 1/2-inch thickness. Dip a 2-1/2-inch biscuit cutter in a little flour, and stamp out as many scones as possible. Reroll dough and continue stamping until you have a total of 12 scones.
5Place scones at least 1/2 inch from each other on a baking sheet lined with parchment paper. Brush tops of scones with remaining 1 tablespoon cream, sprinkle with sanding sugar, and bake until tops are golden and flecked with brown, about 10 to 12 minutes. Remove scones to a wire rack to cool.