Prepare: Preheat your oven to 175°C (350°F). Line an 8" loaf tin with parchment paper and set aside.Add the soy milk and apple cider vinegar to a jug or cup, stir and allow to sit to form vegan buttermilk while you prepare the other ingredients.
Make the tea: Add the loose-leaf chai tea (or filling from teabags) to a cup and add the freshly boiled water. Cover the cup and allow the tea to steep for 10-15 minutes.Squeeze the tea through a fine-mesh sieve to extract the concentrated chai mixture. You should have 40ml (2 ¾ tbsp) concentrated tea after straining.
Combine the wet ingredients: Add the concentrated tea, vegan buttermilk, maple syrup, apple puree, olive oil, vanilla, and orange zest to a medium bowl and whisk to combine.
Combine dry ingredients: To a large separate bowl, add the flour, soft brown sugar, baking powder, spices, and salt, and whisk to combine. *Make sure they're are no lumps of sugar left in the mixture. *(see notes)
Make the batter: Pour the wet ingredients into the dry ingredients and gently whisk them into a batter. Be careful not to over-mix, only stir until they're are no visible pockets of flour.
Bake: Add the cake batter to the prepared loaf pan and bake for 45-55 mins. After 45 minutes, check the cake is ready by inserting a knife or toothpick into it, which should come out clean. If the toothpick has cake residue on it, bake for another 5-10 minutes as needed.Allow the cake to cool in the pan for about 10 minutes before transferring it to a cooling rack.
Make the glaze: Mix all the glaze ingredients together in a bowl. Once the cake has cooled, pour the icing on top. Add more or less depending on your taste.
Storage: Wrap in tin foil or store in an airtight container and refrigerate for up to a week. It will keep at room temperature for a couple of days.
If you can't find loose chai, cut open tea bags and use the tea inside. I've reduced the weight of tea for the recipe if using bags as the tea inside tends to be finer and more intense.
Not all white sugar in the US is vegan, use organic if in doubt.
Remove any lumps of sugar in the dry ingredients, as these will cause dark spots in your baked loaf. Use your fingers to crumble them back to a powder consistency.