Combine the oyster sauce, sriracha, mirin, garlic and sugar in a bowl. Add cayenne pepper to taste.

Blanch the frozen vegetables, drain and set aside. Do the same for the udon noodles.

Quickly sear the tofu in a pan with a dash of olive oil until a light crust develops. Set the tofu aside.

Using the same pan, add some olive oil and wait for it to heat up. Add the sauce ingredients to the pan, cooking the sauce for a few seconds before adding the udon and vegetables.

Stir fry for a few minutes then add the tofu. Season with pepper to taste.