Cut the orange peels into thin strips and place them in a small pot. Cover with water and boil for 5 minutes.

Strain and dry them on kitchen paper towels.

Repeat the same process twice more, using fresh water each time.

Using another pot, boil the 2 1/2 cups sugar with the 1 1/2 cup water over strong heat, stirring constantly until the sugar melts and the mixture boils for a couple of minutes. Add the dry orange peels, stir well so that they are covered in syrup, lower the heat, half-cover the pot and let it simmer for about an hour or until almost all of the syrup is absorbed, stirring from time to time.

Spread 1 cup of sugar on a piece of greaseproof paper and "pass" the peels one by one through it so that they are coated in sugar. Spread them on a cooling rack or greaseproof paper at room temperature and let them dry for at least 12 hours.

Store in a simple glass jar and if you like, tie a ribbon around it and offer it as a present.