White Chocolate-Orange-Pistachio Thumbprint Cookies

Step 1
Combine butter, sugar, egg yolks, and vanilla extract in large bowl. Beat using an electric mixer until well mixed. Add flour, salt, and pudding mix; beat well. Chill dough in the refrigerator for 30 minutes.

Step 2
Preheat the oven to 325 degrees F (165 degrees C). Line a baking sheet with parchment paper.

Step 3
Shape dough into 1-inch balls and place on the prepared baking sheets. Make an indentation in the center of each cookie with your thumb.

Step 4
Bake in the preheated oven until lightly golden around the edges, 10 to 12 minutes. Remove from baking sheet and allow to cool on a wire rack, about 30 minutes.

Step 5
Combine white chocolate chips, milk, and orange zest in a microwave-safe bowl. Heat in the microwave for 1 1/2 minutes, stirring every 30 seconds, until chocolate is melted and smooth.

Step 6
Pour white chocolate mixture into a piping bag and pipe into the thumbprint of the cooled cookies. Sprinkle with chopped pistachios.