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.
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, jalapeo, and onions. Bring mixture just to a simmer; simmer gently for 5 minutes or until noodles are tender. Stir in salt.