Place beef in freezer for 20 minutes. Remove from freezer; cut across the grain into very thin slices. Place beef in a medium bowl. Add soy sauce and next 5 ingredients (through garlic); toss well to combine. Marinate in refrigerator for 1 hour.
Soak noodles in cold water for 30 minutes; drain (noodles will not be tender). Cut noodles with kitchen scissors 2 or 3 times.
Trim roots from enoki mushrooms; separate mushrooms into several large clumps. Cut carrots crosswise into thirds; cut each piece lengthwise into 1/8-inch-thick slices.
Step 2 : Preparing the cooking
Per serving: 332 calories; fat 11g; saturated fat 3.3g; mono fat 4.2g; poly fat 2.6g; protein 24.1g; carbohydrates 32.6g; fiber 3g; cholesterol 45mg; iron 3.4mg; sodium 597mg; calcium 76mg.
Heat a Dutch oven over high heat. Add beef mixture to pan; stir-fry 2 minutes.
Arrange noodles over beef mixture; add stock. Reduce heat to medium-high. Top noodles with enoki, carrots, shiitake, tofu, jalapeño, and onions.
Bring mixture just to a simmer; simmer gently for 5 minutes or until noodles are tender. Stir in salt.