Cook the somen in boiling water for about 3 minutes. Drain the water, rinse the pasta in cold water and set aside. Cut the tofu into cubes and drain with kitchen paper. Fry in a large pan with a little oil until golden brown and also set aside.
Cut the fennel into strips about 1 cm wide. Cut the carrot into thin strips. Fry the fennel, carrots and peas in the pan for about 5 minutes. Add the pasta and tofu. Stir the soy sauce, mustard and sugar beet syrup together and also add so that all the noodles are moistened with the sauce.