First make the custard, heat the milk in a saucepan with 100g of the grated cheese and any of optional flavourings.
Stir until the mix begins to boil, then take off the heat.
Whisk the eggs in a large bowl, then gradually pour in the hot milk mixture, whisking all the while, and season to taste.
Prepare and chop all your optional fillings.
Pour enough of the custard mix into a large enamel dish or deep roasting tin to cover the base, then scatter a third of your fillings on top.
Working one slice at a time, dip the bread into the custard, then layer in the dish.
Pour over the remaining custard, ensuring the bread is evenly soaked, then scatter the fillings on top and dot with any of the optional extra flavourings.
Finish with the remaining 50g grated cheese, then lay another dish or tray on top, gently press down to submerge the bread, and leave to sit for at least 15 minutes and up to an hour.
Lift off the top dish, then bake the strata ina 210C (190C fan)/410F/gas 6½ oven for 25 minutes, until golden brown.
Serve hot or warm.
