Have the pancakes prepared and hot. Melt
Peel and finely chop the onion. Place in a saucepan and generously cover with salt water. Bring to a simmer and cook gently in a covered pan for 10 minutes. Drain and reserve both onion and cooking liquor.
Melt the remaining butter in a saucepan and stir in the flour. Cook gently for a few moments and then gradually stir in about
Thin down the rest of the sauce if necessary to make a coating sauce. Pour over the pancakes and put to heat through in a moderately hot oven (190°C., 375°F., Gas Mark 5) for 10 minutes. Cover with foil and extend the time to 30 minutes if reheating from cold.