Pour chicken stock (or 1/2 cup of chicken stock for PSMF) into a small pan and sprinkle the gelatin evenly over the surface. Leave to soften for five minutes.
Pour heavy cream into a jug (or other 1/2 cup of chicken stock for PSMF), add the Egg White Protein and whisk. Leave to stand for five minutes.
Gently warm the stock and gelatin until completely dissolved. Remove from heat and set aside.
Remove from the heat and set aside.
In a bowl, blend the tuna and cream cheese together well with a hand mixer or stick blender.
Add the sea salt and pepper, lemon juice, and chives.
Pour the heavy cream (or stock for PSMF) and egg white protein powder mixture into the tuna mixture and blend until mixed.
Pour the stock and gelatin mixture into the tuna mixture and stir well with a spatula until completely combined.
Pour into a dish and refrigerate for at least four hours to set.