Dissolve the instant espresso powder in boiling water in a small bowl to create a smooth espresso mixture.

Beat the room temperature butter and confectioners' sugar together at medium speed for about 3 minutes until light and fluffy.

Add the vanilla extract and the espresso mixture to the butter-sugar mix, continuing to blend until perfectly combined.

Gradually add the all-purpose flour while mixing at low speed just until the dough is formed.

Gently fold in the finely chopped toffee pieces until evenly distributed.

Transfer the dough into a gallon-size zipper-lock plastic bag, roll it into a rectangle approximately 9 inches by 11 inches and 1/4 inch thick, then seal the bag.

Refrigerate the dough for at least 2 hours or up to 2 days.

Preheat the oven to 325°F (163°C) and line a baking sheet with parchment paper.

Remove the dough from the refrigerator, open the bag, and place the dough rectangle onto a cutting board.

Cut the dough into desired shapes using a sharp knife or cookie cutters.

Transfer the cut cookies to the baking sheet and poke holes in each cookie with a fork.

Bake in the preheated oven for 18 to 20 minutes until lightly golden around the edges.

Dust the cookies with confectioners' sugar while still hot and transfer them to a wire rack to cool completely.