In a mixing bowl, combine the butter, sugar, and vanilla extract, and then add eggs, one at a time.
Add the lemon zest and the fresh lemon juice.
Slowly add the flour, baking powder, baking soda and salt.
Roll the dough into 1-2" balls depending on what size you want your cookies.
Place on a baking sheet that has a baking mat on it, or a regular baking sheet.
Bake at 350 degrees for 10-12 minutes or just until cookies start to turn a golden brown around the edges.
Place the cookies on a wire rack and allow them to cool.
In a blender pulse the butter, sugar and lemon zest until combined.
Add the eggs one at a time, then the lemon juice, and blend until smooth.
Pour into a saucepan and cook over low heat, making sure that you stir it constantly.
Use a thermometer to see when the curd gets to 170 degrees; it takes about 10-15 minutes.
Then it will begin to thicken.
Remove from the heat and allow to cool, then place in a jar, seal and store in the refrigerator to use within the next two weeks.
Place the butter and the cream cheese in a mixing bowl, and mix with a hand mixer.
Add the powdered sugar, lemon zest and the lemon juice.
Mix on high for 2-3 minutes or until the frosting is a nice consistency.
Pipe the frosting on the cookie alternating with lemon curd.
