1. Set a large pan of water boiling for the noodles.

2. In a small saucepan, combine the peanut butter, rice vinegar, paprika and cayenne. Whisk to combine over low heat. Once combined, add water incrementally, whisking constantly until a loose consistency is achieved. Maintain the pan on a low heat, adding water periodically to maintain the consistency, if necessary.

3. In a wok over high heat, add a neutral oil and heat until smoking. Add the beef, with a splash of soy, and stir fry until browned. Remove from the pan with a slotted spoon.

4. Add the mushrooms to the wok, and a little oil if necessary. Stir fry until medium done, adding soy or fish sauce for seasoning.

5. Add the ginger and carrots, and put a clear glass lid over the wok. Reduce the heat to medium and steam the vegetables for 3-4 minutes, until softened. 

6. Add the noodles to the boiling water.

7. Remove the lid from the wok, add the garlic and bok choy stems. Stir fry for 1 minute. Add the beef back to the pan, with any juices. Stir to combine. Add the bok choy green and stir fry until wilted.

8. Turn off the heat. Pour the peanut sauce into the wok and stir to cover. Drain the noodles and toss with a little toasted sesame oil.

9. Serve in bowls.