I decided to make some separate ginger cookies and snickerdoodles after making many of the combined gingerdoodles.  Three different-looking cookies from one recipe!  
Recipe from Bakergirl (again, I used butter instead of shortening.)

Ginger-Spice Sandwich Cookies.  These are so outrageously amazing…the filling is flavored with lemon zest and juice!

Cookie recipe (I didn’t use the cayenne pepper)
Instead of the mascarpone filling, I used:

Lemon Filling
1/2 cup butter, softened
1/2 cup powdered sugar
1 tablespoon lemon juice
2 teaspoons lemon zest

Cream butter and powdered sugar.  Add juice and zest, beat until smooth.