Based on the recipe below from Recipezaar,
For the Pumpkin Woopie Pies, I would substitute a
spice cake mix for the chocolate cake mix
and 1 (15 oz) can solid pack pumpkin.
Eliminate most of the milk and flour.
Since the spice cake mix doesn't contain pudding, a little milk might be needed.
Easy Pumpkin Spice Cookies (Cake Mix)
Ingredients
1 (18 1/4 ounce) box spice cake mix
1 (15 ounce) can solid-pack pumpkin (the small can)
1 cup chopped walnuts (optional) or chopped pecans (optional) or 1/2 cup raisins (optional)
1 cup cream cheese frosting (optional)
1. Preheat oven to 350°F.
2. Spray cookie sheets lightly with vegetable spray (Pam).
3. In a large bowl, mix together the cake mix and pumpkin
with a fork or mixer until well blended; stir in nuts or raisins, if desired.
4. Drop by large rounded spoonfuls onto the cookie sheet;
they don't flatten out much so however you place them on the
sheet is pretty much how they'll look after baking.
5. Bake for 8 to 15 minutes, depending on the size of your cookies.
6. Allow cookies to cool on baking sheet for up to 5 minutes before
removing to a wire rack to cool completely.
7. Frost, if desired.
8. How many cookies you get depends on how large you make them of course -
just increase your baking time if making larger cookies
(it's truly difficult to burn these, but they will get crispier & less moist);
Mine, made with a medium size cookie scoop, take 13-15 minutes to bake and
yield about 3 dozen.