Preheat oven to 350. Line a cookie sheet with parchment paper.
Cream the butter and sugars in a medium bowl.
Mix in egg yolk.
Add dry ingredients and mix until incorporated.
Scoop dough with a medium cookie scoop on the prepared pans.
Bake for 12-14 minutes or until golden brown.
Cool completely.
Lemon Curd
In a medium saucepan, off the heat, whisk the egg yolks with the sugar.
Stir in the zest.
Drizzle in the lemon juice while whisking.
Add pats of butter.
Place on the stove over medium-low heat. Cook, whisking constantly, until thickened, about 5 minutes.
Cool completely.
Lemon Mousse
In a large bowl with an electric mixer, whip the heavy cream until stiff peaks form. Transfer to a separate bowl.
Whip the cream cheese, sugar, and lemon extract until light and fluffy. Add ⅓ of the whipped cream and mix well.
Gently fold in the remaining whipped cream.
Assembly
Layer broken pieces of cookies with lemon curd and lemon mousse in small glass cups.
Use a piping bag to pipe the mousse and/or curd for a nice presentation.
Top with a berry, if desired.
Notes
No-Bake Option - Swap in your favorite store-bought shortbread cookies for the homemade cookies.Semi-Homemade Option - Use store-bought cookies and lemon curd. Make the lemon mousse and layer as directed.