Honey-Dipped Cookies

Combine sugar, honey, water, lemon juice, and lemon slices in a saucepan; bring to a boil. Simmer, stirring occasionally to dissolve sugar (15-20 minutes). Set aside to cool completely. Dip shortbread cookies into cooled syrup, then finely chopped pistachios to coat. Transfer to a wax paper-lined plate until set.