First cream the butter and sugar together into creamy mixture.
Add vanilla extract and mix. Now add shifted flour and fold flour.

If cookie dough is sticky, you add more 1tbsp flour.
Now divide the dough in three equal parts. Keep one part aside as that will be the center part.
Add orange food colour to one part of dough and mix gently.
Add green food colour to one part of dough and mix gently.

Now roll 3 parts of the dough into equal rectangular shape block.
Stack the three parts of the dough so that green is on bottom, and orange colour on top and plain colour in middle.
Now wrap the dough in cling wrap and keep in refrigerator for one hour.

Before taking out the dough from refrigerator, pre heat the oven at 180C for 10minutes.
Take a dough and cut into half inch thickness.
Place cookies on baking tray lined with parchment paper. Make sure to leave space between cookies as they will spread in oven.

Bake cookies at 180 C degree for 15mins.
Each oven is different so make sure you don't over bake them, when the edges turn slightly golden then it is a indication to take them out.
Once cookies are cooled, store them in airtight container.