Start by sifting the powdered sugar for the glaze to remove any lumps—this ensures a smooth, professional-looking finish. While that's done, cut the unsalted butter into small cubes so it softens to room temperature quickly.

In a medium bowl, whisk together the flour and salt, then set aside. In a separate bowl, cream together the butter and sugar for 2-3 minutes until the mixture is light, fluffy, and pale.

Add the vanilla extract and mix until fully combined. Add the flour and salt mixture and mix on low speed just until a cohesive dough forms.

Roll the dough out between two pieces of parchment paper to 1/2 cm thick. Cut into heart shapes using a cookie cutter and transfer to a parchment-lined baking sheet.

Cover the baking sheet with plastic wrap and refrigerate for 30 minutes. Preheat your oven to 170°C (335°F).

Bake the cookies for 10-12 minutes until set but still pale and tender. Remove from the oven and let them cool on the baking sheet for 2-3 minutes, then transfer to a wire rack.

In a small bowl, combine the sifted powdered sugar, strawberry puree, butter, milk, and lemon juice. Mix until smooth and spreadable.

Separate the cooled cookies into two equal groups. Dip one half of the cookies into the strawberry glaze, coating the top surface evenly.

Spread about 1 teaspoon of strawberry jam onto the top of each remaining cookie, then gently press a glazed cookie and a jam-topped cookie together to create a sandwich.

Let the assembled cookies set on a plate for 15-20 minutes so the glaze firms up slightly before serving.