Preheat oven to 375 degrees. In a meduim bowl, whisk together flour, baking soda, and salt. Set aside.
With an electric mixer, beat butter and sugars until light and fluffy. Beat in eggs, one at a time, beating after each addition. Beat in espresso powder.
With mixer on low speed, beat in flour mixture until incorporated. With a rubber spatula or wooden spoon, mix in hazelnuts.
Drop heaping tablespoons of dough onto three baking sheets, 1 1/2 inches apart. Bake, first two sheets together, until golden, about 12 minutes, rotating sheets front to back and from top to bottom halfway through. Repeat with remaining sheet. Cool cookies on sheets 2 minutes; transfer to a wire rack to cool completely. Serve, or store in an airtight container up to 3 days.