Add egg yolks and salt to a sous vide bag. Remove air and seal.
Cook in a sous vide bath at 65 degC for 32 minutes.
To stop the cooking, plunge into an ice bath until cold to touch.
Crispy tofu
Cut the tofu into bite sized pieces.
To extract some moisture from the tofu, place on paper towels.
Sprinkle a little salt onto the tofu pieces.
Place some more paper towels on top of the tofu. Place a tray on top of those paper towels, and weigh it down with a 400g can of tomatoes or something of similar weight.
Leave for 20 minutes. The paper towels will become wet.
Heat the oil in a skillet to 160 degC.
Fry each piece of tofu until golden brown.
Allow to drain on fresh paper towels.
Serving
Warm the egg yolk sauce a little. Be very careful. They will go from runny to solid very quickly. A few seconds in a microwave will do it, or immerse in warm water for a few minutes.
Arrange the crispy tofu on a plate and pour the egg yolk sauce over it.