Gypsy Tart

Found this recipe when I was living down in Kent.
It is very sweet!

14oz tin evaporated milk
12oz dark muscovado sugar
10 inch shortcrust pastry case cooked.

Preheat oven to 400F. Whisk milk and sugar together for 10-15 minutes until light and fluffy. The mix should be coffee coloured. Pour the mix into the pastry case and bake in the oven for 10 minutes. The gypsy tart will have a slightly sticky surface but will not set completely until it has been left to cool.
Serve cold.
It depends a lot on the correct amount of whisking if it sets properly or not, sometimes I managed it, sometimes not but it didn't go to waste!