Preheat your oven to 190°C (375°F) and line a baking tray with parchment paper.

In a bowl, sift together the flour, cornstarch, and salt, then set aside.

Cream the softened butter with the icing sugar until smooth and fluffy.

Beat in the eggs one at a time, mixing well after each addition.

Gradually add the dry mixture into the wet ingredients and mix until a soft dough forms.

Stir in the vanilla extract.

Scoop and roll the dough into small balls, about 1 tablespoon each, and arrange on the prepared tray.

Use your thumb (or the back of a small spoon) to gently press an indentation in the center of each dough ball.

Fill each indentation with a small spoonful of your favorite jam (strawberry, raspberry, apricot, etc.).

Bake for 15 minutes, or until the edges are lightly golden.

Let cookies cool on the tray for a few minutes before transferring to a wire rack.

Serve once cooled — or store in an airtight container for up to a week (if they last that long).