Put the shallots, bay leaf, wine and vinegar in a heavy saucepan. Cook over medium heat until the liquid has reduced to a pasty red mixture. Remove the bay leaf.

Over very low heat, whisk the butter into the wine mixture one piece at a time, whisking constantly until all the butter is absorbed and you have a creamy sauce. Stir in the cream.

Add salt and pepper as needed and serve spooned over the steak. Serve with lightly smashed Yukon gold potatoes.