Make 4 jars of apricot and orange blossom jam to share with your friends and family. Place the apricots into a large preserving pan with the sugar and mix well. Cover and set aside for 4 hours. Add the lemon juice and heat gently, stirring occasionally until the sugar has completely dissolved. Then turn up the heat and bring to a boil. Boil for 15 minutes, keeping the mixture at a rolling boil for the entire time, stirring once in a while, if necessary. Spoon a teaspoon of the mixture onto a cold saucer and allow to cool for a few seconds. Then push the jam with your finger. If it wrinkles, it has reached setting point; if not, return to the heat in bursts of 2-3 minutes until it has. Remove from the heat and skim the surface using a straining spoon then stir in the orange blossom water and butter. Allow to cool for 30 minutes, then ladle into 4 sterilized jam jars. Cover each with a circle of wax paper and allow to cool before covering each with a tight-fitting lid. The jam will keep for up to 6 weeks in a cool place. Delicious served with slices of lightly toasted brioche. The key to storing jams and curds is to make sure that you use sterilised jars. Jams can be kept in a cool dark place for up to a year, once opened, they must be kept in the fridge and consumed within 2-3 weeks.