How can I extend shelf life of my cakes? I need to bake a cake and send it over to a friend. It might take 5-7 days for the cake to reach him. What are the possible ways available to extend shelf life at least till the day it reaches him, especially during the transit?

My current recipe consists of dry spices, honey, sugar, white floor, eggs, baking soda, baking powder, warm water, coffee powder, almond, oil.
Increasing the amount of sugar, eggs, and oil should make the cake last longer. The sugar binds water, which slows the cake from drying out. The eggs and oil slow the starch in the flour from recrystalizing, which is what causes staling.