Prepare the Shortbread Dough

1. Cream Butter and Sugar
   • In a mixing bowl, beat softened butter and caster sugar until light and fluffy. Add vanilla extract and mix well.
2. Mix Dry Ingredients
   • In a separate bowl, sift together plain flour and salt. Gradually add to the butter mixture, mixing until a soft dough forms.
3. Chill Dough
   • Shape the dough into a disk, wrap in plastic wrap, and refrigerate for 30 minutes to firm up.

Bake the Cookies

4. Preheat Oven
   • Preheat the oven to 160°C (320°F) and line a baking tray with parchment paper.
5. Roll and Cut Dough
   • Roll out the dough on a floured surface to about 1/4-inch thickness. Use a heart-shaped cookie cutter to cut out cookies. For half the hearts, cut a smaller heart in the center to create the top layer.
6. Bake
   • Place cookies on the prepared tray and bake for 10-12 minutes, or until edges are lightly golden. Cool completely.

Assemble the Cookies

7. Fill with Jam
   • Spread a thin layer of strawberry jam onto the base cookies. Top with cookies that have a cut-out center to form a sandwich.

Make the Glaze

8. Mix Glaze Ingredients
   • In a small bowl, combine strawberry puree, icing sugar, melted butter, and milk. Stir until smooth.
9. Decorate
   • Dip the top of each sandwich cookie into the glaze and let it set on a wire rack.