Cream butter, cream cheese, and sugar until light and fluffy
Add egg yolk, lemon extract, and lemon zest and mix until combined.
Add flour and salt and mix until well combined.
Scoop dough into cookie press and press cookies onto an ungreased baking sheet using one of the flower disks.
Bake in preheated oven for 10-12 minutes.
Allow to cool for a few minutes on cookie sheet, then transfer to wire rack to cool completely before icing.
For the Buttercream:
Combine the butter and lemon juice in the bowl of an electric mixer. Cream together on low speed until the ingredients are completely combined and fluffy.
Add the powdered sugar to the butter mixture one cup at a time, mixing well between each addition.
When the icing is thick and creamy and has reached the desired consistency, add the lemon zest and mix to combine.
Separate the icing into two bowls (a small bowl for the green icing and a larger bowl for the pink icing). Add pink food coloring to one bowl and green food coloring to another bowl. Mix each bowl of buttercream until the desired color is reached.
Using a star tip, pipe pink icing onto the petals of each flower. Finish by adding a dot of green icing to the center of each flower.
Make them Gluten Free: The only change needed to make these gluten free cookies is the substitute of gluten-free flour. The other ingredients naturally don't contain gluten. Bob's red Mill and King Arthur both make very nice gluten free baking flours.