Start by sifting the powdered sugar for the glaze to remove lumps. Set it aside.

Cut the butter into small cubes and let it soften to room temperature. In a medium bowl, whisk together the flour and salt and set aside.

In a separate bowl, cream the butter and sugar together for 2 to 3 minutes until light and fluffy. Add the vanilla and mix until combined.

Add the flour mixture to the butter mixture and mix on low speed just until a dough forms. Do not overmix.

Roll the dough between two sheets of parchment paper to about 1/2 cm thick. Cut into heart shapes and place them on a parchment-lined baking sheet about 1 inch apart. Cover and refrigerate for 30 minutes.

Bake the chilled cookies for 10 to 12 minutes until set but still pale. Let them cool on the baking sheet for 2 to 3 minutes, then transfer to a wire rack to cool completely.

In a small bowl, combine the sifted powdered sugar, strawberry puree, butter, milk, and lemon juice. Mix until smooth and spreadable. Adjust with a little more milk if too thick or more powdered sugar if too thin.

Divide the cooled cookies into two groups. Dip half of them into the glaze and let the excess drip off.

Spread about 1 teaspoon of strawberry jam onto each of the unglazed cookies. Gently press a glazed cookie on top of each jam-covered cookie to create a sandwich.

Let the cookies sit for 15 to 20 minutes so the glaze can set before serving.