In a bowl, add in butter and icing sugar. Just using a spatula, mix everything together to combine. Then add in yolk, lemon zest and vanilla extract. Again mix to combine.

Add in flour in 2 additions, mixing just to combine after each addition. Place the dough on a cling film, wrap it tightly and chill in the fridge for 2 hours or until it's firm.

Take a piece of dough and press it evenly into a 2.5 inch (6.5 cm) tart mould. Cut off excess dough with a knife. Using a fork, prick the base so that it doesn't puff up while baking. Repeat the same with the rest of the dough. Place them on a baking tray. Place them in the freezer for 10 minutes.

Bake in a preheated oven at 340ºF (170ºC) on the lowest rack for 15 minutes. Remove from the oven and leave to cool completely. Once cooled, remove the tarts from the moulds by flipping them and tapping a bit on the back of the back of the base to help releasing them. Set aside.

In a bowl, add in cream cheese and icing sugar. Using a whisk, mix until just combined. Then add in egg, vanilla extract and mix to combine also. Finally add in milk and mix everything together.

Take 1 tablespoon more or less, of cream cheese mixture and add some red food coloring to it. Mix well and set aside. Do the same with using green color.

Take 1 tart shell and put some strawberry jam in it. Then spoon in the cream cheese mixture on top until the rim of the tart. Gently shake it to smooth out the surface.

Dip the back of a chopstick or something similar in size, into red colored cream cheese mixture and make 2 dots on the tart. Using a toothpick, dip it in green colored cream cheese and make 2 lines under each red dots. Using another clean toothpick, run it across the 1 red dots and 2 green lines, creating a flower with stem and leaves. Do the same with the other dot and repeat with the rest of the tarts. Place them on a baking tray.

Bake in a preheated oven at 340ºF (170ºC) on the lowest rack for 15 minutes or until the center sets. Remove from the oven and cool completely. Chill in the fridge for 2 hours before serving. Enjoy!