Preheat oven to 450F. Line a baking sheet with a silpat liner for easy cleanup; otherwise, lightly grease a baking sheet.
Whisk together the flour, sugar, baking powder, salt, nutmeg, dried cranberries, and rosemary in a large bowl.
Cut in the butter with a fork or using two butter knives until it looks like coarse meal. Stir in the half and half. (The dough should come together, but not be too wet.)
Shape the dough into a ball, then flatten it into a disk; wrap it in plastic wrap and chill 10 minutes in the freezer.
Turn the dough out onto a lightly floured surface. Roll or press the dough out to a circle about 7 to 8 inches in diameter and 3/4 inch thick. Cut the circle of dough into 8 equal wedges.
Transfer the scones to the prepared baking sheet, lightly brush the tops with a little milk, and bake until puffed and light golden brown on top and bottom, about 14 to 16 minutes. Cool completely.
Once cooled, whisk together all ingredients for the glaze. Dip the tops of the scones into the glaze, letting it run down the sides; sprinkle a few dried cranberries and rosemary leaves on top, if desired. Place the scones onto a wire rack and let the glaze set completely before serving.
Instead of half and half, you could use whole milk or cream for this recipe.
Make Ahead: You can make the dough the night before; instead of chilling it in the freezer for 10 minutes, wrap it up and refrigerate it overnight (or up to 3 days in advance). Bake the scones straight from the fridge the morning you want to serve them.
Take a couple minutes to freshly grate your nutmeg because it makes all the difference in terms of flavor! I recommend using a microplane to grate whole nutmeg.