01 - In a large mixing bowl, beat the softened butter with the powdered sugar using an electric mixer until the mixture is light and creamy, about 2 minutes.
02 - Add the lemon zest and vanilla extract, blending until fully incorporated.
03 - Sift together the flour and salt. Gradually mix into the butter mixture on low speed until just combined and the dough forms.
04 - Divide the dough in half. Shape each into a disc, wrap tightly in plastic wrap, and refrigerate for 30 minutes.
05 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
06 - On a lightly floured surface, roll out one dough disc at a time to 1/4-inch thickness. Cut into rounds with a 2-inch cookie cutter, placing half on baking sheets.
07 - With a smaller cutter, remove the centers from half of the cookies. These will be the tops for sandwiching.
08 - Bake cookies for 11 to 13 minutes or until the edges are just golden. Transfer to a wire rack and cool completely.
09 - Stir the lemon juice into the raspberry jam until smooth.
10 - Spread about 1/2 teaspoon of jam mixture on the flat side of each solid cookie. Gently top with a cookie featuring the cut-out center to form a sandwich. Dust with powdered sugar if desired.