Beat together the butter and powdered sugar until very soft.
Add the vanilla extract and orange zest, then the cornstarch.
Slowly add the flour and salt.
Transfer to a piping bag fitted with a medium star tip.
Pipe 1.5-2" rosettes on a parchment lined baking sheet. Chill.
Bake at 375F/190C for 13-15 minutes until golden brown around the edges. Let cool.
Beat together all ingredients for the vanilla buttercream then transfer to a piping bag with a star tip.
Put 1-1.5 teaspoons of raspberry jam on the bottom of one cookie.
Swirl buttercream on the bottom of another cookie. Sandwich together by pressing the buttercream lined cookie on top of the jam.
