Cream together the butter and powdered sugar until light and smooth.
1 ½ cups unsalted butter, 1 cup powdered sugar
Add in the vanilla extract and salt and mix them through.
1 tsp vanilla extract, ¼ tsp salt
Sift over the flour (1 cup at a time), mixing well between each addition.
3 cups all-purpose flour
Divide the dough in half and roll each half to 1/4-inch thick with parchment paper.
Chill overnight or for at least 2 hours.
Bake cookies in a preheated oven to 350, on a baking sheet lined with baking paper or a Silpat mat.
Bake for about 15 minutes or until the edges turn golden brown. Cool the cookies on a wire rack after gently lifting them off the baking tray.
Cool completely, then fill a piping bag with dulce de leche and pipe the filling onto one cookie, layering a second cookie on top.
2 cans dulce de leche
Roll the sides of the dulce de leche sandwich cookies in coconut to finish them.
2 tbsp desiccated coconut