01 -
Preheat oven to 350°F (180°C) and line baking sheets with parchment paper or a silicone baking mat.
02 -
Using a stand mixer fitted with the paddle attachment, combine the butter, sugars, egg, lemon zest, and limoncello. Beat on medium speed until creamy and free of lumps.
03 -
In another bowl, combine the flour, baking powder, and salt. Mix well.
04 -
Gradually add the flour mixture to the butter mixture and beat on medium speed until just combined.
05 -
Scoop 1 1/2 tablespoon sized balls of dough onto the cookie sheets, spacing them 2 inches apart.
06 -
Bake for 9-11 minutes or until golden brown around the edges with no uncooked centers.
07 -
Remove the cookies from the oven and transfer to a wire rack to cool.
08 -
In a small saucepan, combine all icing ingredients except the powdered sugar. Heat on low until the sugar melts, then bring to a boil over medium heat.
09 -
Boil for 3 minutes, stirring occasionally. Remove from heat and immediately pour into a heat-proof bowl. Whisk in the powdered sugar and let cool for 10-15 minutes to thicken.
10 -
Spread the icing onto the cookies and allow to cool. The icing will thicken as it cools.