I can find recipes using buterscotch sauce, but not a recipe for buterscotch tart - sorry Kieth.
Found this using Google - from Delia Smiths forum -
Someone asked this very question some years ago, and several people answered. I cut and pasted their replies and here they are!! I tried the second one and it was indeed very sweet.
I have an AUTHENTIC school recipe for butterscotch tart - from when I was in school in the 80's.It's obviously been scaled down and actually only makes quite a small tart - 7".
1/2lb shortcrust pastry
3oz demerara sugar
3oz margarine
3/4oz plain flour
1/2oz dried milk (e.g. Marvel)- made up with a little water to make a runny paste
Bake pastry blind in tin. In saucepan melt margarine over low heat, add sugar, stir, add milk paste and sieve in flour. This doesn't appear to be any precise art: cook for about 5 mins until it thickens, looks right and, most of all, tastes right!! Pour into the pastry case and leave to cool (I put it in the fridge for a few hours).Hope it's like your old school butterscotch tart!
Don't know if this is any help, as I'm sending it from Australia, so I doubt it would be an English school recipe!!
Butterscotch Tart Filling.
1 cup milk, 1 tablespoon honey, 1 teaspoon vanilla, 1/2 cup sugar, 2 tablespoons butter, 1 tablespoon custard powder.
Method: Put all ingredients into saucepan. Bring to boil, stirring until thickened. Pour into pastry shell when cool. Refrigerate. Top with whipped cream and decorate as desired.
