Heat oven to 400°F. Combine flour blend, sugar, baking powder, lemon zest and salt in large bowl; cut in butter with pastry blender or fork until mixture resembles coarse crumbs. Stir in whipping cream; mix until dough holds together. Stir in cranberries and 3/4 cup white baking chips.
Turn dough onto lightly floured surface; knead 5 to 10 times or until dough is smooth. Divide dough into 4 equal pieces; shape each piece into 8×1-inch log. Cut each log into 4 (2-inch) pieces; cut each piece in half diagonally to form small triangles.
Place scones, at least 1 inch apart, onto ungreased baking sheet. Bake for 9 to 11 minutes or until golden brown around edges. Cool completely.
Combine remaining baking chips and shortening in small microwave-safe bowl. Microwave on MEDIUM (50% power) 30 seconds; stir. Continue microwaving and stirring every 30 seconds until chips are melted and smooth. Drizzle scones with melted chocolate.
Gluten-Free Flour Blend: To make flour blend, combine 2 cups rice flour, 2/3 cup potato starch, 1/3 cup tapioca flour and 1 teaspoon xanthan gum. Use appropriate amount for recipe; store remainder in container with tight-fitting lid. Stir before using.