Prime rib is a star all on its own, but a little gravy or sauce takes it to a whole new degree of delicious. This sauce is super easy to make (do it while the meat roasts), and is a fabulous way to top beef.
3 cups heavy cream
2 teaspoons grainy Dijon mustard
3 Tablespoons prepared horseradish
1/2 teaspoon salt
1/8 teaspoon freshly ground pepper
Place the cream in a medium saucepan and bring to a boil. Reduce the heat to a simmer, and allow the cream to reduce by half, stirring occasionally. (The cream may boil up early in the process, so keep your eye on it. This can take up to an hour.)
Once the cream is reduced and thick, remove from the heat and add the remaining ingredients. Keep warm until ready to serve.
This sauce reheats well on the stove over low heat.