Line a loaf pan with parchment paper. Preheat oven to
Start by making the homemade buttermilk by combining oat milk and apple cider vinegar. Set aside for 5-7 minutes. In a large bowl combine the melted vegan butter with both granulated and brown sugar. Add in the grated carrots, buttermilk, and vanilla extract, and mix. Add in the plain flour, baking soda, baking powder, and chai masala. Fold together until combined.
Pour into the lined baking loaf pan. Bake for 40-45 minutes or until a toothpick comes out clean when inserted in the center. Allow to cool to room temperature.
For the frosting, beat together the softened vegan butter and cream cheese. Add in the vanilla extract and chai masala, and mix. Slowly add in the icing sugar and mix. I like to use a handheld whisk for this step but a spatula will work too!
Dollop the frosting over the cooled cake, and spread over with an offset spatula.