To make the reduced cider: Cook the fresh apple cider on high until it has reduced to just over ¼ cup – you’ll notice it becomes thick and has the consistency of syrup when it’s done. Set aside to let cool. For the cake you will use ¼ cup (60g) and the rest (about 1 TB) will go into the glaze.
Preheat the oven to 350 F. Prepare a large bundt pan (one that holds 10 cups of batter) with baking spray.
In the bowl of a stand mixer zest the oranges over the sugar then rub between your fingers to release the orange oils. Then, add the eggs and affix the paddle attachment then beat on high until the mix is light and fluffy – about 5 minutes.
With the mixer on medium speed, very slowly drizzle in the olive oil to create an emulsion. Once all of it is in, beat another minute.
Add the flour, cinnamon & spices, baking powder and soda to a bowl and whisk to combine.
With the mixer on low, add the dry mixture then slowly pour in the cider, then the orange juice then the buttermilk.
Pour batter into prepared bundt pan. Bake for 45-60 minutes, until a cake tester comes out clean.
To make the glaze: sift the powdered sugar into a bowl and whisk it with the boiled cider, vanilla and salt and just enough milk to make it pourable. Pour over the cake once the cake has cooled. Over the cake zest an orange and grate a whole nutmeg.
Best served the day of baking, store extra cake in an airtight container.