Preheat the oven to 350 degrees. Place two silicone baking mats onto baking sheets
Add butter, sugar, and powdered sugar in a large bowl and beat until smooth and fluffy (about 4 minutes)
Add in the eggs and vanilla and beat the mixture until it¹s all incorporated
In a separate bowl, mix the flour, salt and baking powder. Add in the butter/sugar mixture to the this bowl and mix until everything is combined.
Put the bowl with the final dough mixture on top of the heated oven until the dough is softened (this makes it easier to pipe the cookies).
Fill a piping bag fitted with a large tip, with the dough (I prefer a large star-tip).
Pipe the dough into shapes onto the silicone baking mats. You can get really creative here and do any shape you want - just make sure to make an even number of each shape so that your sandwich has two matching sides.
Bake cookies for 8-12 minutes depending on the size of your cookies. The edges will start get a little golden brown.
Place the cookies on a wire cooling-rack, and do a light dusting of powdered sugar.
Once the cookies are fully cooled sprinkle another round of powdered sugar on the top and apply the edible glitter. Edible glitter can be super fine in size. So to apply it, I dipped a (clean) watercolor paintbrush into the glitter and flick it onto the cookies
Once the cookies are decorated, flip every other cookie upside down (I tend to flip the less pretty ones). Fill a piping bag fitted with a small tip, with Bonne Maman Raspberry Preserves. Pipe the jam onto the flipped over cookies and let sit for a few minutes (about 10 minutes).
Start pairing up your sandwiches!