Butter the 6 muffin tin moulds really well.
Cut the sheets of fillo into large enough squares to fit the moulds plus extra for a little overhang, and butter them as you lay them in. Use 3 sheets per mould. Bake in the oven for 10 minutes at 160c/gas 3
To make the filling beat together the egg yolks cream, lemon juice and cheese in a bowl. Stir in the vegetables and season with salt, pepper and nutmeg. Spoon into the filo tarts, insert a ball of ricotta cheese and top with grated Parmesan or Gruyere and bake until the mixture is just set, about 15-20 minutes.
Filling