1Scrub mussels and remove hairy beards from them. Heat a small amount of olive oil in a fry pan, add onion and garlic and cook until onion is soft. In a small pan cook bacon until browned then drain on absorbent paper.
2In a large saucepan add enough water that will cover mussels and bring water to boil. Add mussels to pan, cover and cook for a few minutes or until mussels open. drain and discard any mussels that do not open. Remove shells completely from some of the mussels, remove half the shell from others and leave some complete. This is for presentation and ease of eating.
3Wash saucepan and return to medium heat combine wine, lemon juice, water, both stocks, and onion garlic mixture, bring liquid to boil then reduce heat to a simmer, add cream and bacon.
4Remove pan from heat. In a bowl lightly beat egg yolks and add a few tablespoons of soup mixture to egg and mix, then add to soup, return pan to a low heat add mussels and basil and stir until heated through.