Drain the liquid from the cans of tuna, reserving 1 tbsp of the liquid from the can. Add the tuna and reserved liquid to a bowl and break the tuna up with a fork.
Add in the almond flour, chopped parsley, lemon juice and zest, red onion, scallions, mustard, egg, salt and pepper. Stir until well mixed and then taste. Adjust the seasoning as desired.
Form the mixture into 6 patties and place on a parchment paper lined plate or tray. Place the patties in the fridge for a minimum of 20 minutes, chilling them will help them hold together when cooking.
When ready to cook, place the olive oil in cast iron skillet on medium heat. Once hot add in the patties and let them cook for approximately 4 minutes until a golden crust forms. Flip and cook on the other side.