Wash the apricots, split them to remove the pit, and cut them each into 4 or 5pieces.
Put the apricots with the sugar in a food processor and blend to a creamy consistency.
Transfer to a saucepan, add the lemon juice, and turn on the heat to medium. Bring to a low boil and cook for 10 minutes, stirring constantly.
Transfer to a bowl. When the apricots are cool, break the egg into a small bowl and beat it well. Add it to the apricots, beating it in thoroughly.
Add the butter and return the mixture to the saucepan, turning on the heat to low. Beat constantly until the cream is uniformly blended and warm. Do not let it boil; other-wise, bits of the egg white will separate and harden.
Pour into 6 serving cups, let cool completely, then refrigerate. If you prefer, it can be poured into a single serving bowl instead of individual cups.