Preheat the oven to 350F/180C/gas mark 4. Cover two cookie sheets with parchment paper.

Sift together the dry ingredients.

In a large bowl, mix the vanilla, sugar, oil, milk and egg together; add flour mixture slowly, mixing until it's evenly incorporated.

Using a level wet tablespoon, drop on a parchment-covered cookie sheet. Smooth them to the size and shape you want when baked, using wet fingers or a spatula. These will spread a little. Bake for 12 to 15 minutes until the tops spring back when pressed and begin to crack slightly. Let cool completely.

Soak the dates in hot water for at least an hour until very soft. Remove the pits. Melt the coconut oil over low heat (or by placing the jar in a larger container of hot water.)

Put the granulated sugar in a dry blender and blend until powdered. Remove to a bowl.

Put the dates in the blender with the soy milk, soy milk powder, peppermint extract, and coconut flour. Blend until very smooth. With the blender running, slowly pour in the coconut oil until well blended and very thick. Add food coloring or chlorophyll until it's the color you want. Scrape out into a bowl and add enough of the powdered sugar to make a frosting consistency.

Assemble the whoopie pies by spreading a thin layer of frosting on the bottom of one cookie, then sandwiching another cookie on top. Store in the refrigerator in a lidded container, placing waxed paper in between layers of cookies so they don't stick together.