Preheat oven to 350 degrees F. Lightly grease baking sheets.
Combine the canola oil and brown sugar. Mix in the pumpkin and eggs. Add the flour, salt, baking powder, baking soda, 1 tsp vanilla, cinnamon, ginger, and cloves. Mix well.
Drop heaping teaspoons of dough onto the greased baking sheets. Bake at 350 degrees F for 10-12 minutes. Let cookies completely cool, then make sandwiches by filling two cookies with Whoopie Pie Filling (below).
Whoopie Pie Filling
Beat egg white and mix well with the milk, 1 tsp vanilla, and 1 cup of the confectioners' sugar. Beat in the shortening and the rest of the cup of confectioners' sugar. Beat until fluffy.