1 cup (5 ounces) all-purpose flour
¼ teaspoon baking soda
¼ teaspoon salt
4 teaspoons instant espresso powder
1 ¼ teaspoons warm tap water
½ cup plus 2 tablespoons (4⅓ ounces) sugar
5 tablespoons unsalted butter, melted and cooled
1 large egg
½ teaspoon vanilla extract
Adjust oven rack to middle position and heat oven to 350 degrees. Line baking sheet with parchment paper. Whisk flour, baking soda, and salt together in bowl.
Whisk espresso powder and water together in medium bowl until espresso powder dissolves, then whisk in sugar and melted butter until combined. Whisk in egg and vanilla until smooth. Gently stir in flour mixture with rubber spatula until soft dough forms. Fold in toffee bits.
Working with 2 tablespoons dough at a time, roll into
balls and space them 2 inches apart on prepared sheet.
Bake cookies until edges are set but centers are still
¼ cup Heath toffee bits
soft and puffy, about 13 minutes, rotating sheet halfway
through baking. Let cookies cool slightly on sheet. Serve
warm or at room temperature. (Cookies can be stored at
room temperature for up to 3 days.)