Bring a medium pot of water to a boil. Add the soba noodles and cook them according to the package directions.

Drain the noodles in a colander and rinse them well with cool water.

Return the noodles to the pot and toss them with the sesame oil.

Coat the bottom of a medium skillet with 1 tablespoon of canola oil and place it over medium heat.

When the oil is hot, add the tofu in an even layer and cook it for 10 minutes, flipping once or twice to achieve browning on multiple sides.

Remove the tofu from the skillet and transfer it to a paper towel-lined plate.

Heat the remaining tablespoon of oil in large pot over medium heat. When the oil is hot, add the garlic, ginger, and white parts of the scallions. 

Sauté the mixture for about 1 minute, or until very fragrant.

Add the water to the pot. Raise the heat and bring it to a boil.

Add the carrots and simmer it for about two minutes, until the carrots become bright orange and slightly tender.

Remove the pot from heat. 

Place the miso into a small bowl and ladle in a bit of the hot liquid from the pot. Whisk until the mixture is smooth.

Stir the miso mixture into the pot, along with the spinach. Stir until the spinach is wilted. Season the soup with soy sauce to taste.

Divide the noodles and tofu among four bowls, then ladle the soup overtop. Sprinkle with sesame seeds and the green parts of the scallions. Serve.