Place all of the dry ingredients into a bowl. Mix to combine and set aside.
Add the butter and brown sugar to the bowl of a stand mixer. Beat together on low/medium speed for 5 minutes. It should be light and fluffy when done. Be sure to scrape the sides throughout the beat time.
Next, add the egg, vanilla, and lemon zest to the creamed butter and sugar. Mix until combined.
Add the lemon juice and mix until combined.
Slowly add the dry ingredients to the wet ingredients and mix until just combined. Be sure there are no flour clumps at the bottom of the mixing bowl.
Transfer the cookie dough to an airtight container and refrigerate for at least 2 hours or overnight.
Preheat the oven to 350℉ and line a baking sheet with parchment paper.
Scoop the cookies with a 2-tablespoon scoop and roll them into a ball. Because these cookies spread a bit more than others, we prefer to bake 6 to a baking sheet.
Bake for 9-11 minutes.
Let rest for 5 minutes before transferring to a cooling wrack. Let the cookies cool completely.
Prepare the frosting. Place the cream cheese and butter into the bowl of a stand mixer. Whip together until well blended and fluffy. If the cream cheese and butter are not warm enough there might be lumps when whipping together. If that is the case whip for another minute.
Next, add the vanilla, lemon juice, lemon zest, and powdered sugar to the bowl. Starting on low, mix together until well blended. The speed can be increased once the sugar has been incorporated.
Store in an airtight container and refrigerate until ready to use.
Frost each cookie and garnish with lemon zest.