Trim the tenderloin roast of fat and silver skin (see photo on left). Silver skin is a silvery-white connective tissue. It does not dissolve when the tenderloin is cooked, so it needs to be trimmed away. If the silver skin is not trimmed off, it will cause the tenderloins to curl up into the shape of a quarter moon.
Score the meat at various points across the width of the tenderloin and set aside.
In a small bowl, combine soy sauce and ground mustard. Using your fingers, rub the soy/mustard mixture onto the roast. On a piece of wax paper, combine fennel seeds and caraway seeds; roll the coated roast in the seed mixture to coat evenly. Wrap tightly in plastic wrap and refrigerate at least 2 hours or overnight.
Preheat oven to 375 degrees F. Bring roast to room temperature before cooking. Unwrap plastic wrap from the roast.
Place fat side up onto a rack in a shallow baking pan. Bake, uncovered, 30 to 45 minutes or until a meat thermometer inserted into thickest part of the roast registers 140 degrees F. to 145 degrees F.
This is the type of cooking and meat thermometer that I prefer and use in my cooking. I get many readers asking what cooking/meat thermometer that I prefer and use in my cooking and baking. I, personally, use the Thermapen Thermometer shown in the photo on the right. To learn more about this excellent thermometer and to also purchase one (if you desire), just click on the underlined: Thermapen Thermometer.
Remove from oven and transfer onto a cutting board; let roast stand 15 minutes before carving (meat temperature will rise 5 to 10 degrees after it is removed from the oven). Transfer onto a serving platter and serve with Savory Mustard Sauce.
Savory Mustard Sauce:
1/4 cup water
2 tablespoons ground mustard
1 teaspoon cornstarch
3 tablespoons light corn syrup
1 tablespoon cider vinegar
In a small saucepan over medium heat, combine water, ground mustard, and cornstarch. Stir in corn syrup and cider vinegar; cook and stir until thickened and bubbly. Cook and stir another 2 minutes. Remove from heat and let cook before using.