Found this on an interesting blog www.frombatoparis.com - thank you Cristina
On the menu at Balthazar in Soho New York CityFor these Eggs Meurette (serves 2) you will need:For the red wine sauce: combine using a fork, one teaspoon of soft butter (room temperature), with one teaspoon of flour. Knead it into a ball. Refrigerate (this is called “beurre manié” (Once you are at it, you can make more “balls” of beurre manié, keeping them in the freezer for other sauces that you will make in the future; remember the proportion flour, butter is always 50/50). Put the wine in a saucepan, let it boil, then reduce the heat and let it simmer till reduced to a third (it should have a syrup consistence). Add the beurrie manie. Whisk until well dissolved, and the sauce coats a wooden spoon.Put the slice of toasted bread on a dish, accomodate one dollop of caramelised onions on it, then the poached egg. Serve with greens. Place the two slices of bacon on the greens. Spoon the sauce over the egg.