Preheat the oven to 325°F (160°C) and line a baking sheet with parchment paper.

In a small bowl, dissolve the espresso powder in hot water; set aside to cool slightly.

In a mixing bowl, cream together butter and powdered sugar until light and fluffy.

Mix in the vanilla extract and dissolved espresso.

In another bowl, whisk together flour, cocoa powder, and salt.

Gradually add the dry mixture to the wet ingredients, mixing until a soft dough forms.

Scoop out small portions of dough (about 1 teaspoon each) and roll into oval shapes.

Use a butter knife to press a shallow line down the center of each to mimic a coffee bean.

Arrange on the prepared baking sheet and bake for 12–15 minutes, until set.

Cool completely before serving.