To ask how to make white sauce with onions using flour?

[BiddyPop]

I make white sauce using cornflour.

I know flour based versions need to be "cooked out" before adding the milk.

MIL has handed me the job without any instructions.

Help!

Currently the onions are cooking in a small amount of water, that's the only instruction I got

BBC recipe works:

https://www.bbcgoodfood.com/recipes/white-sauce

I usually fry the onions in butter, then start the white sauce in the same pan.

Cornflour in a pan with some melted butter. Stir to a paste. Add onions. Keep stirring and add milk slowly.

Thank you both!

I would simmer the milk with the onions first, then use the infused milk, but I don't know if that's what your MIL meant!

This, to me, is onion sauce! I fry the onions gently in plenty of oil/butter until soft but not coloured, then add flour (a flat tablespoon per half pint of milk) and seasoning and continue frying to cook out the flour. Then add the milk gradually, stirring vigorously all the whole to get out all the flour lumps. Bring to the boil, summer for a few minutes, check the seasoning, serve!
Delicious served with boiled gammon, mash and cabbage 😁