Line an extra-large baking sheet with parchment paper or foil; set aside. In a large bowl, combine flour, the 1/2 cup sugar, baking powder, apple pie spice and salt. Using a pastry blender, cut in cold butter until mixture resembles coarse crumbs. Stir in the 1 cup finely chopped apple. Make a well in center of flour mixture.
In a small bowl, combine the 2 eggs and 3/4 cup whipping cream. Using a fork, stir egg mixture into flour mixture; stir until just moistened. Dough will be thick. Using a 1/4-cup ice cream scoop or measuring cup, scoop dough into mounds and place on prepared baking sheet. Don't flatten.
In a small bowl, combine the egg yolk and 1 tablespoon whipping cream. Brush some of the mixture over the top of the dough mounds. Place an apple slice on top of each dough mound, pressing down until about 1-inch thick. Brush with remaining egg yolk/whipping cream mixture; sprinkle with additional sugar.
Bake in a 375 degree F oven for 15 to 17 minutes or until lightly browned. Cool on baking sheet on a wire rack for 5 minutes. Remove scones from baking sheet. Cool slightly. Serve warm with Spiced Maple Butter. Makes 15 scones.
In a small mixing bowl beat butter, maple syrup and apple pie spice with an electric mixer on medium speed until light and fluffy. Cover and chill for up to 1 week. Serve at room temperature. Makes 3/4 cup.