To make beef gravy, combine cooked roast beef drippings with 2 cans of beef broth and heat the mixture to medium. Make a paste with 2 tablespoons corn starch and 4 tablespoons of beef broth, add the paste to the mixture and whisk the gravy until it thickens.
To make beef gravy without meat drippings, melt 1/4 cup of butter in a saucepan and then whisk in 1/4 cup of flour. Remove all visible lumps and add 1/4 teaspoon each of salt and pepper to the butter and flour mixture. Reduce the heat to low and slowly add 2 cups of beef broth while stirring constantly. Add 1 teaspoon of Kitchen Bouquet seasoning sauce, increase the heat to medium and stir the gravy until it boils and thickens.
To make slow-cooker Bavarian beef roast with gravy, place a 3-pound beef roast in a slow cooker. Mix 1 tablespoon of creamy horseradish sauce, 3 tablespoons of stone-ground mustard and 1 envelope of brown gravy mix in a bowl and spread the mixture over the roast. Pour 1/2 cup of beer or apple juice around the edges of the roast and cook the mixture on low heat for nine to 10 hours.
To make the gravy, blend 1/2 cup of water with 3 tablespoons of flour in a saucepan until smooth. Pour the cooking juices from the slow cooker into the saucepan and heat the mixture to a boil over medium-high heat while stirring constantly. Season with 1 tablespoon of chopped chives.