Whisk two eggs and 290ml milk together and slowly incorporate sieved flour to create a batter.
Stir chopped herbs and seasoning into the batter, then fry three pancakes and let them cool.
Sear the beef fillet in a hot oiled pan, cool it, then brush with egg white and mustard.
Wrap the cooled beef fillet in a single layer of the herb pancakes.
Roll out the puff pastry, brush with egg wash, and seal it tightly around the pancake-wrapped beef.
Apply a final layer of egg wash to the top of the pastry.
Bake on silicon paper for 12 minutes at 180°C and rest for 5 minutes.
Blanch the spinach in hot water, refresh in cold water, and add to a pan of reduced double cream.
Simmer until the cream mixture is thick and rich, then remove from heat.
Slice the beef, top with the creamed spinach, and serve.