Add the softened butter to a mixing bowl.

Add the powdered sugar and beat with an electric hand mixer until light and creamy.

Add the vanilla extract and mix until well incorporated.

Gradually add the all-purpose flour, cornflour, and salt.

Mix gently with a spatula until a soft cookie dough forms. Chill the dough for 15–20 minutes.

Divide the dough into 18 equal portions and roll each into a smooth ball. Place them on a lined baking tray and gently flatten.

Make a small indentation in the center of each cookie using your thumb or the back of a spoon.

Fill each indentation with raspberry jam.

Bake until the cookies are lightly golden around the edges. Let them cool completely.

Dust with powdered sugar if desired.

Serve the raspberry jam sandwich cookies.