In a medium bowl, whisk together vegetable broth, soy sauce, dark soy sauce, corn starch, liquid sweetener, rice vinegar, and ground pepper. Set aside.

Bring a large pot of water to boil. Add ramen noodles and simmer for 2-3 minutes. Drain and rinse under cold water.

Heat sesame oil in a skillet over medium-high heat. Add diced tofu and sliced vegetables. Sauté for 5-7 minutes until golden brown.

Pour the prepared sauce into the skillet with tofu and vegetables. Simmer on medium-low for 2-3 minutes until thickened. Add drained noodles and toss together.

Cook for an additional 3 minutes, stirring continuously to absorb the flavors. Adjust seasonings if needed.

Serve hot, garnished with chopped scallions and sesame seeds.