Walnut Cauliflower

The following recipe came from a cookbook my sister bought for me in 1986. There are some fascinating recipes in 'Supercookery!' She bought it because I was so taken when she made the following dish from it. She had a covered tureen that held the cooked cauliflower whole, making a beautiful presentation. My family doesn’t really like cauliflower, so I don’t get this very often at all!

1 oz. (2 tablespoon) butter
1 oz. (1/4 cup) flour
12 fl. oz (1.5 cups) milk
6 fl. oz. single cream (3/4 cup light cream)
1 egg, lightly beaten
2 fl. oz (1/4 cup) cider vinegar
2 tablespoons soft brown sugar
2 tablespoons prepared French mustard
4 oz. (2/3 cup) walnuts, coarsely chopped and toasted
1 medium-sized cauliflower, cooked until tender and kept hot.

In a medium saucepan, melt butter over moderate head.
Remove from heat and use a wooden spoon to stir in the flower, making a smooth paste.
A little at a time, add the milk and cream, stirring constantly to avoid lumps.
Add the egg, vinegar, brown sugar and mustard.
Return the pan to low heat and cook, stirring constantly, for another two to three minutes or until the sauce is thick and smooth. Do not allow the sauce to boil or the egg will scramble.
Stir in the toasted walnuts and cook for a moment more, stirring constantly.
Remove from heat, place cooked cauliflower on a warmed serving dish and pour the sauce over it.
Serve at once.