Whisk the flour, sugar, baking powder, salt, together in a large bowl. Zest the orange over the bowl and whisk it into the flour mixture. Add the butter to the flour mixture and combine with a pastry blender until there are only pea-sized crumbs. (See recipe notes if you do not have a pastry blender)
In a liquid measuring cup that holds at least 1 cup, whisk ½ cup heavy cream, the egg, and vanilla extract together. Drizzle over the flour mixture, add the cranberries, then mix it all together until there are no dry patches of flour. (It should look like a big sticky clump. I usually end up having to press things together toward the end)
Use your hands to work the dough into a ball in the bowl. Add flour as needed. (If it seems too dry, add 1-2 more Tablespoons heavy cream, but be sparing). Press into a 9-inch disc and, with a butter knife or pizza cutter cut into 8 wedges.
Place scones on a lightly floured baking sheet with a splat mat. Try to space them equally from one another. I alternate which scones are pointing up and which are pointing down to maximize space.
Optional: Brush the top and sides of the scones lightly with heavy cream and sprinkle with sugar.
Refrigerate for at least 15 minutes. Meanwhile, preheat oven to 400°F (204°C).
Bake for 22-25 minutes or until the bottom edges are golden brown and tops are lightly browned. Remove from the oven and allow to cool so you don't burn your mouth.