This classic sauce made with a sweet, smoky fortified wine from Portugal has an amazingly complex flavor but very few ingredients. It's the sauce of choice for Beef Wellington or a simple roasted beef tenderloin, and it's the perfect complement to game, lamb, poultry, roasted vegetables, or pork, especially an Easter ham. You can substitute other fortified wines like Marsala or Port for different but equally luscious results.
Bring the diluted Demi-Glace Gold® to a simmer in a small saucepan. Add the Madeira and continue to simmer until the mixture is reduced back to about 2 cups.
Whisk in the butter and season to taste with salt and pepper.