With a paddle attachment, combine dry ingredients. Add butter until it’s a crumbly mixture.
In a separate bowl, use a mixer fitted with a paddle attachment to combine the Smith’s Sour Cream and egg yolk until very smooth.
Add in flour mixture and mix until the dough comes together.
Form into a disk, wrap in plastic wrap and chill at least 4 hours.
In a bowl, mix the cream cheese, egg, sugar, vanilla and lemon zest.
Dust counter with confectioners sugar, roll out the pastry into a square about 1/8" thick into 3” x 3” squares. Place a tsp of filling in the center of each square.
Lift up one square, gathering the center of the square around the filling into a cup.
Place the cookie in a mini muffin tin and repeat with the remaining squares. Refrigerate for 30 minutes.
Preheat oven to 375 F. Bake until golden brown, 20 to 25 minutes.