Before even leaving Maine, vegan whoopie pies went from nowhere in my notes to the top of my list of future posts. I needed these iconic, pillowy confections ASAP!
Rather than writing a recipe from scratch, I analyzed the ingredients for "Whoopie Pies" in Baking Across America: A Vintage Recipe Road Trip by B. Dylan Hollis. I only needed to replace:
"Buttermilk is easy!" I thought. Adding 1 Tbsp (15 mL/g) of vinegar or lemon juice to 1 cup (240 mL/g) of certain non-dairy milks creates a thick, reliable substitute. Eggs, however, could be harder...
To review from my vegan boxed brownie experiments, eggs perform a variety of tasks including (but not limited to):
Two of these tasks are accomplished by other components in the original recipe. In the presence of acidic ingredients such as natural cocoa powder and buttermilk, baking soda provides lift; meanwhile, shortening contributes moisture/richness.
I only needed binding/structure!
In many baking recipes, the bulk of binding/structure comes from flour. Binding/structure may therefore be increased by 1. adding more dry ingredients, 2. reducing wet, or 3. both.

I chose 3. both. While I could have simply omitted eggs, I opted to substitute them with 1 Tbsp (15 mL/10 g) cornstarch each. It worked perfectly! Such a powder is dense enough to prevent these cake cookies from spreading too much in the oven, but light enough to preserve their classic, cloud-like texture.
Thank you B. Dylan Hollis for helping me fulfill my Maine craving! The following recipe is adapted from "Whoopie Pies" in Baking Across America: A Vintage Recipe Road Trip.
Use gram measurements if you can. I retained Hollis's standard volume measurements, but they don't exactly match his more accurate metric measurements.
makes 18-20 complete whoopie pies
Bring "milk" to room temperature.
Preheat oven to 375°F/190°C. Line 2 baking sheets with silicone or parchment.
Into a medium bowl, sift flour, cocoa, cornstarch, baking soda, and salt. Set aside. Combine "milk" and vinegar (to make vegan buttermilk) in a separate bowl, then set near dry ingredients.
In a large bowl, beat shortening and sugar on hi until smooth. Incorporate extract.
On lo speed, alternately add about 1/3 of the dry ingredients followed by 1/3 of the "buttermilk". Continue until everything is uniformly mixed.
Using a #50 cookie scoop or 2 spoons, evenly space no more than 10 mounds of batter (about 1 1/2 Tbsp, or 22.5 mL each) onto prepared baking sheets. Bake 8-10 min.
Allow each batch to cool slightly before transferring with an offset spatula onto a wire rack. Cool completely before assembling.
In a large bowl, beat shortening on hi until fluffy. Incorporate extract(s).
Alternately add about 1/4 of the powdered sugar followed by 1/4 of the water. Continue until everything is uniformly mixed.
Transfer frosting to a piping or zip-top bag. Generously pipe an even layer onto half the cookies, then sandwich with the other half.
Store leftovers in an airtight container at room temperature up to 3 days, or refrigerated up to one week. Return to room temperature before enjoying.
If you need dinner to go with this dessert, I suggest my Maine "Lobster" Rolls!
Gratitude is the most scrumptious seasoning!
Thank You ♥
From the Bottom of My Hearth, Christi of Does It Vegan?