In a mixing bowl, beat ½ cup of softened unsalted butter and 1 cup of powdered sugar using an electric mixer on medium speed for about 2-3 minutes until light and fluffy.

Add ½ cup of pistachio paste, 1 egg yolk, 1 teaspoon of vanilla extract, and ½ teaspoon of almond extract. Stir until smooth and combined.

In a separate bowl, whisk together 1 ¾ cups of all-purpose flour and ½ teaspoon of salt. Gradually add this mixture to the wet ingredients, stirring until just combined.

Scoop portions of dough, rolling each into a smooth ball. Place them on a baking sheet lined with parchment paper, leaving space between each ball.

Preheat oven to 350°F (175°C). Bake cookies for 10-12 minutes until lightly golden around the edges.

Allow cookies to cool on the baking sheet for about 5 minutes, then transfer to a wire rack to cool completely.

In a clean mixing bowl, mix ½ cup of additional pistachio paste, ½ cup of softened butter, and 1 cup of powdered sugar until smooth. Adjust with milk if necessary.

Spread the pistachio cream filling between two cookies to create sandwiches. Press gently to distribute filling.

Dust finished cookies with powdered sugar and sprinkle with crushed pistachios for garnish.