Yaki Udon (Stir-fried Udon Noodles with Soy Sauce)

When using frozen udon noodles: Lightly sprinkle water over the udon noodles. Then, place them on a microwave-safe plate, cover with plastic wrap, and microwave at 1000W for about 2 minutes.
When using fresh, dried, or pre-cooked udon noodles: Boil the udon noodles according to the package instructions and drain in a colander.
Cut the carrot and onion into long, bite-sized strips. Tear the cabbage into bite-sized pieces. Cut the pork belly into pieces about 0.6 inch (1.5cm) wide.
Put the seasonings (sake, mirin, and soy sauce) in a bowl and mix them together.
Heat oil in a pan. Once the pan is hot, add the pork, sprinkle it with salt and black pepper, and sauté until the color changes. Then, add the vegetables in order of firmness (carrot, onion, and cabbage), and stir-fry until they become tender.
Move the sautéed ingredients to one side of the pan and add the udon noodles to the empty space. Pour the seasoning liquid from the bowl onto the udon noodles and mix well to coat evenly. Once the udon noodles are coated with the seasoning liquid, combine them with the other ingredients. Then, cover the pan with a lid and steam over low heat for 2 minutes.
Remove the lid from the pan and cook until most of the remaining moisture has evaporated.
Serve on each plate and sprinkle bonito flakes on top.