Special equipment: a bundt or tube pan
Preheat the oven to 350 F.
Fill a large ziptop bag with the granulated sugar, salt and orange zest. Seal the bag and shake it around until the zest and sugar are totally combined. Cut the chilled biscuits into quarters. Add the biscuit pieces to the bag, seal it and shake/toss it around until all the biscuit pieces are coated in the orange sugar. Pour the pieces into a bundt or tube pan and set aside.
In a medium pan over medium heat, melt the butter. Stir in the brown sugar, vanilla and orange juice until just barely combined. Pour the mixture all over the biscuit pieces, scraping the pan to get all the butter/brown sugar out. Let it settle for a second, then place the pan in the oven.
Bake until the top of the biscuits are golden brown, about 25 minutes. Transfer the pan to a rack and let it sit for at least 10 minutes (but no more than 15), then turn the cake out of the pan onto a cake plate. Let cool briefly before serving.
When it first comes out of the pan, the melted sugar/caramel will be a little on the hot side. Wait a few minutes after turning it out before serving.