In a large mixing bowl, cream together 1 cup of softened unsalted butter and 1 cup of powdered sugar until light and fluffy, about 3-4 minutes. Gradually add in 3 cups of all-purpose flour, 2 large room-temperature eggs, 1 teaspoon of vanilla extract, and 2 tablespoons of milk. Mix until a smooth dough forms, then cover the bowl with plastic wrap and chill it in the refrigerator for at least 30 minutes.

While the dough chills, prepare the filling by combining 2 cups of chopped nuts in a mixing bowl. If desired, add 1/2 cup of raisins or chopped dates for extra sweetness and texture. Stir well to ensure the nuts and any additional fillers are evenly mixed. Set the bowl aside to let the flavors combine.

After chilling, preheat your oven to 350°F (175°C) and lightly flour your work surface. Remove the dough from the refrigerator and roll it out into a rectangle of about 1/8-inch thickness, using a rolling pin.

Sprinkle the prepared nut mixture evenly over the rolled-out dough, leaving a small border around the edges. Gently press the filling into the dough with your hands to help it adhere.

Starting from one end of the rectangle, carefully roll the dough tightly to encase the filling. Make sure the seam is on the bottom to keep the cookies from unraveling during baking. Using a sharp knife, slice the roll into 1-inch pieces to create individual cookies. Place the slices on a baking sheet lined with parchment paper.

Bake the cookies in the preheated oven for 15-20 minutes, or until they turn a lovely golden brown on the edges.

After baking, allow the cookies to cool on the baking sheet for 10 minutes. Then, carefully transfer them to a wire rack to cool completely. Dust the cooled cookies with powdered sugar before serving.