Preheat the oven to 180°C.
Add the water, cubed butter and salt to a saucepan and bring to a simmer.
Remove from the heat and add the flour.
Mix with a spatula and return to the heat to dry out the dough slightly.
Transfer the dough to the bowl of a stand mixer, and use the paddle attachment to mix as you add the eggs one by one, ensuring each one is fully incorporated into the mixture before adding the next.
Pipe the eclairs onto a baking tray lined with greaseproof paper. Prepare an egg wash, and brush it over the eclairs.
Even out the surface of the eclairs with the back of a fork, then sprinkle with sesame seeds and bake for 40 minutes.
Finely dice a shallot, shell the beans and juice the lemon.
Bring a pot of water to the boil and simmer the beans for 5 minutes. Drain and set aside.
Cut the smoked salmon into strips.
Whisk the cream cheese with the lemon juice, then add in the shallot and season.
Transfer the cream cheese mixture into a piping bag fitted with a Saint Honoré nozzle.
Slice the eclairs down the middle and pipe in the cream cheese mixture, topped with a few slivers of smoked salmon and sprinkle with fava beans.
Add a few sprigs of coriander as a garnish, and serve.
