Cook onion for 20 mins till soft

Blend onion for a smooth paste for 1 min

Light fry beef fillet for 30 seconds on each side, and then spread dijon mustard sauce on the top side, put onion mixture

Egg and water mix to seal the pastry, seal the edges with the egg mix, and press with folk

Make a small cross on the top to let steam out, finish with egg wash on top of the pastry,

200c oven for 15 mins, should be ready