To make neroli, blossoms from the bitter orange tree are soaked in water before being steam distilled - the water left behind is orange flower water. For hundreds of years, this treasured ingredient brought a delicate, floral hint of orange to Middle Eastern sweets and drinks. Its popularity as a fragrance and flavouring grew in Europe during the Renaissance, so much so that bitter orange began to be cultivated in the South of France expressly to make it.