The White-Gold War Torte is the 150% Alliance points booster.
The recipe for the White-Gold War Torte requires a recipe scroll for the Molten War Torte. You'll need to combine that with Chef Arquitius's Lost Thesis.
The Chef Arquitius's Lost Thesis tome can be obtained from completing a Battleground; while it is exceptionally rare, it is more likely to drop from groups that are victorious in battle.
The White-Gold War Torte requires a unit of Molten War Torte, as well as a new ingredient, Mourning Dew. The Mourning Dew item is found, very rarely, from crafting resource nodes throughout Cyrodiil.
Item: White-Gold War Torte Recipe
Creation: Recipe Molten War Torte + Chef Arquitius's Lost Thesis = White-Gold War Torte Recipe
Special Ingredient: Mourning Dew
Location: The Chef Arquitius's Lost Thesis occasionally drops from completing Battlegrounds.