You will need:
Carefully remove the yellow yolks from the boiled egg halves and place in a bowl. Add a couple of teaspoons of beetroot juice and a couple of tablespoons of mayonnaise making sure to adjust based on how many egg yolks you're using or how pink you want them to be. Mix it all together until it's smooth, then spoon the mixture into the yolkless egg whites.
If you have some mixture left over you can make some cute little sandwiches.