Heat oil in a pan over medium low heat. When hot, add in flour and stir constantly until it turns light brown, about 15-20 minutes.
Once brown, add in curry powder and mix briefly, about 30 seconds. Take off from the heat and set aside the roux.
Add garlic, ginger, onions, carrots, and celery to a large pot with oil or a splash of water. Cook until onions turn translucent.
Add veg broth, applesauce, tomato paste, and Worcestershire sauce. Bring to a boil, add roux, then lower heat and simmer for 5-10 minutes, stirring occasionally to dissolve the roux.
Add zucchini and mushrooms and continue to cook until tender. Taste and add salt/pepper as needed.
In the meantime, prepare the udon noodles according to the package instructions. Rinse and drain, then set aside.
Make sure the roux has completely dissolved in the soup, then add tofu and gently mix. Turn off heat.
Divide noodles into bowls and spoon curry mixture over top. Sprinkle with shichimi togarashi for a spicier flavor. Enjoy!
Notes
*For substitution suggestions, refer to the above paragraph in the post titled "Substitutions".