1. The first thing to do is to make a thickwhite sauce that will be the base ofthe turnover filling. Bring the milk to asimmer, then add the butter and flourpaste.
2. Whisk the paste into the simmeringmilk and allow it to boil for 3-4 mins,whisking gently all the time to preventit from catching. You should now have avery thick white sauce. Cool the sauce ina bowl. Fry the mushrooms in the oil for3-5 mins until golden, then leave to cool.
3. Place the ham, cheese and mushroomsinto a bowl, then gradually add the whitesauce until everything is well coated.Finally, add the herbs.
4. Roll out the pastry on a floured surfaceto about the thickness of a £1 coin andcut out 4 saucer-size rounds (about18cm wide), re-rolling the trimmings ifyou need to.
5. Brush the edges of eachround with beaten egg. Spoon themixture onto 1 side of each round, thenfold over and seal the edges well. Theturnovers can now be frozen for up to1 month.
6. Brush the turnover with theremaining egg, then chill for 30 mins.
7. Heat oven to 200C/180C fan/gas
8. Place the turnovers on a baking sheetand bake for about 35 mins until puffedup and golden. Leave to cool slightlyand enjoy warm.