Udon Noodles with Black Pepper Tofu

Press the tofu for 10-30 minutes. Meanwhile prep the veggies and combine the noodle sauce ingredients in a bowl. Set aside.
Bring a pot of water to a boil. Add the udon noodles and gently toss with tongs - just until they fall apart (about 60 seconds). Drain and set aside.
Combine the soy sauce, cornstarch, sesame oil and black pepper in a shallow bowl. Whisk to combine. Cut the tofu into squares and place in the marinade. Gently toss to coat.
Heat some oil in a pan over medium heat. Once hot, add the tofu and cook, flipping, until all sides are browned. Remove the tofu and place the pan back on the stove.
Add some more oil to the pan with the garlic, ginger and whites of the green onions. Cook for 60 seconds. Add the celery, carrots and a splash of the noodle sauce. Toss to combine and cook until the veggies are slightly tender. Add the noodles, spinach and remaining noodle sauce. Toss until combined and the spinach is wilted. Add the tofu back to the pan and give everything a final toss.
To serve, add equal amounts to 4 bowls and top with sesame seeds, the remaining green onions and more red pepper flakes.