Wash bok choy, cut off the green tops, chop them coarsely, and place in a bowl. Slice the white parts about 1/2-inch thick and place in another large bowl. Cut the carrot into matchsticks and add it to the white bok choy bowl. Slice the mushrooms, and put them with the carrots. Slice the bell pepper thinly and add it to the bok choy greens. Dice the tofu and set aside.
Place the miso and cornstarch into a bowl and gradually add the water as you whisk it to combine smoothly. Add the remaining sauce ingredients and set aside.
Heat a large non-stick skillet or wok (or regular skillet that has been rubbed or sprayed lightly with canola oil). When it’s hot, add the garlic and stir for about 30 seconds. Add the white bok choy/carrot mixture and 2 tablespoons water and cover immediately. Steam for about 2 minutes. Add the bok choy greens, cover, and cook until just wilted, about 1-2 minutes. Stir in the tofu and the sauce and cook until tofu is heated through and sauce is slightly thickened. Serve immediately over noodles or whole grain.
*The sesame oil adds only 1 gram of fat and 10 calories to the entire dish (all three servings combined).