rainbow valentine cookie

saw this beautiful rainbow valentine cookie on facebook and decide to give it a try. first thing I need to take the colouring from yong jie.

ingredients:
170g butter
155g icing sugar
1 teaspoon vanilla extract
3 egg yolks
310g cake flour
colourings
spinkles
egg white
1 teaspoon water

method:
1. cream the butter with icing sugar
2. add in the vanilla extract and mix
3. add 3 egg yolks and mix
4. add in the sieve cake flour and mix well to form a dough
5. spilt the dough into 3 parts.
6. keep one part of the dough as it is. spilt the other 2 parts of the dough into 6 and mix the colouring into each small part and mix well
7. measure the height of your heart shape cookie cutter.
8. divide the height of the heat shape cookie cutter into 6 and roll the colour dough the thickness as required.
9. ensure the roll out dough of all the same size to make stacking easier later.
10. chill the roll out dough to set the shape.
11. mix 1 teaspoon of water to egg white
12. brush some egg white on the colour dough and stack another colour dough on it. repeat till all colour dough are stack up in a pile
13. press them together with a rolling pin lightly.
14. cut off the uneven side from the pile.
15. put the pile in the fridge to set
16. cut the pile according the thickness of the cookie cutter
17. cut out the heart shape from the dough and set aside
18. brush some egg white on the cut out heart shape dough and stack all of them together
19. slowly roll out the original dough into strips and place them on the stack up heart shape dough.
20. ensure all the original dough cover up the heart shape roll nicely into cylinder.
21. set it in the fridge again
22. get ready a plate of sprinkles
23. brush some egg whites on the dough and roll it on the sprinkles.
24. ensure the roll are cover in sprinkles
25. slowly cut them up into the thickness you want for the cookie
26. bake at 170 degree for about 10-12 minutes