In a blender, pulse together the black peppercorns, mirin, oyster sauce, sesame oil and sugar to a thick paste. You're looking for a sweet, peppery flavour. Adjust to your liking - my measurements aren't exact, they are simply where I started off from...
Put some water on the boil in a pan for the pasta.
Heat some olive oil in a wok. When hot, stir fry together the sliced pepper and mushrooms. Glug some kecap manis on them to give a little colour. Season with a bit of salt. When soft, tip them into a heatproof container and keep aside.
When your pasta water is boiling, add the pasta. It will cook in about 6 - 10 mins (depending on whether you opted for fresh or dry), and that's more than enough time to finish off the beef.
In the wok, heat a little more oil. Fry together the beef, garlic, ginger and shallots. When the beef is cooked through, add the mushrooms and peppers you cooked previous. Add the pepper sauce from the blender. Mix well and turn down the heat.
Drain the pasta and add to the beef wok. Add the chopped coriander and spring onions, mix everything together well, and serve immediately. Squeeze over fresh lime before eating.