In a food processor, or in a large bowl using your fingers, mix the butter, sugar, zest, vanilla, flour, and salt until crumbly. Knead the dough in the bowl until it comes together. Place the dough on a large sheet of lightly floured parchment paper and roll it to a thickness of 1/4 inch. Trim the edges to form a large circle. Cover and refrigerate for 30 minutes.
Heat oven to 300° F.
Cut the dough into 16 wedges. Transfer the parchment paper and dough to a baking sheet. Bake until golden, about 45 minutes; let cool.
Divide the shortbread, oranges, and ice cream among bowls. Drizzle the oranges with the honey.
In Advance: Refrigerate the dough overnight and bake it early in the day. Or use store-bought shortbread in place of the freshly baked to save time.
To Freeze: Place the unbaked, unsliced circle of dough in a large resealable bag. Store for up to 3 months.
To Reheat: Thaw the dough overnight in the refrigerator. Slice and bake according to the recipe.