Are there any 70's/80's school cooks?

You have to know where to look!
Was it this by any chance?

Chocolate Flan recipe

Ingredients & Quantities
Pastry

180g of Flour
40g of Margarine
40g of Lard
Pinch of Salt
30ml of Water
Filling

1200ml of Water
90g of Sugar
90g of Cornflour
1/2tsp Vanilla Essence
110g of Dried Milk
30g of Cocoa Powder
Method
Line a tin with the pastry, crimp the pastry edges, prick well and blind bake.
Whisk the dried milk with most of the water.
Blend the cornflour, sugar and cocoa with the remainder of the water.
Bring the milk to the boil and add the cornflour mixture, as for blancmange.
Cook for 10 minutes and pour on to the pastry case.
Decorate with piping cream or dust with icing sugar.
Notes: any flavoured cornflours could be used instead of the normal cornflour and cocoa powder.

Ooh thank you, I'll give this a try.

Our school had wonderful dinners, but that chocolate tart was the only one I hated. My favourite was the cornflake tart.

. My school days are long ago. School dinners were wonderful for steamed pudding and custard days. Horrible for prunes and custard days. I have hated prunes ever since

Chocolate concrete was fab. Anyone remember that? It was usually served with a squirt of mock cream on it, which was horrid, but once you'd scraped that off, it was great to smuggle into your regulation knickers pocket to keep you going through the afternoon classes.
I liked the sago (frogspawn) and semolina puds tho. I was a strange child!