Melt your butter in a medium saucepan over a low heat. Once melted add in your flour and whisk to combine to form a smooth consistency.
Immediately add in your white wine and simmer for 2 minutes.
Add in a third of the stock and stir well until everything is combined and without lumps. Add the rest of the stock, gravy browning, and tomato puree. Mix to combine.
Simmer to allow it to reduce to the consistency you like.