Prepare 8 coddled eggs by boiling them for 5 minutes in water. Allow to cool down at room temperature. Cut the slices or bread in circles with a 10 cm diameter. Butter on both sides. On each toast, place 3 slices of tongue (or grilled bacon), then the coddle egg.
Place the egg yolks in a pan with 4 tablespoons of cold water (or juice of stewed shallot, or white wine). Whip until there is a froth, then cook the resulting sabayon on a very low flame. It should increase in volume and become mossy. Remove the pan from the flame when the temperature of the sabayon is close to 60 °C (you should be able to touch it without burning yourself) and each whipping should make the bottom of the pan appear (start with an electric whip and finish by hand). Incorporate the clarified butter (that has melted softly after having removed the white layers) by stirring the sauce with a whip. Season the sauce with lemon juice, fine salt and pepper. Mix. Set the sauce aside covered in warm place.
Glaze the eggs with your sabayon sauce. You can decorate your eggs with truffle.