for the fondue:
For the fillet in crust:
Brown the two sides of the beef fillets in a heated non-stick pan, add salt, pepper and let them cool turning off the burner.
Wrap each portion of beef fillet with tho slices of cooked ham and cover it with a layer of puff pastry.
Brush egg yolk on the puff pastry and bake in the oven at 180° for 20/25 minutes.
In the meanwhile, heat the fontina and the cream in a water bath. When the cheese has melted, add the egg yolk and stir until the fondue is creamy.
When the fillet crust is golden, take it out from the oven and let it rest for some minutes before serving.
Pour the fondue in the dish and place the crusted fillet cut into two parts on top.