To make roux: Melt 125g butter in a frypan over medium heat. Stir in flour, reduce heat to low, and cook until roux is a light chocolate colour. Season with basil and thyme. Remove from heat.
Heat oil in a saucepan over medium heat. Saute eschalots until tender. Stir in wine, and simmer until liquid is reduced by half. Strain eschalots from wine, and return wine to frypan. Stir in cream and 4 tablespoons butter; heat until butter is melted. Stir in 2 to 3 tablespoons of the roux, until mixture thickens. Cook on low heat for about 5 minutes to eliminate starchy flavour. Season with salt and pepper.