Prepare the shortcrust pastry: work the butter with sugar and vanilla until you obtain a creamy consistency, then incorporate the egg (in the photo you see 2 because I had made double the quantity, but there were really too many biscuits, so it was better to halve the quantity with the quantities that I wrote in the ingredients).

Also add flour and lemon peel and knead until you have a homogeneous mixture.

Form a ball, wrap it with cling film and leave it to rest in the fridge for at least 30 minutes.

Take the dough again and divide it into 7 equal parts: leave one neutral and color the other 6, red, orange, yellow, green, blue and purple respectively.

Form a loaf with the purple dough, then roll out the other doughs (separately) creating thin sheets.
Wrap the blue dough around the purple dough, then wrap the green dough around the blue and the yellow dough around the green.

Continue with orange and red and conclude with the neutral pastry.

At this point you can cut your roll into 1-2 cm slices and then divide each slice in half.
Place your biscuits on the baking tray lined with baking paper, slightly spaced apart, and cook for about 10 minutes at 180°C in a pre-heated ventilated oven.

The rainbow biscuits are ready, all you have to do is let them cool before serving them.