Cook the ramen noodles following the packet instructions and place them in ice-cold water or rinse them with cold water for a good while to stop them from cooking further.
Heat the vegan butter or coconut oil in a pot over medium heat. Add finely chopped leek and cook for about 10 minutes. Stir until it becomes soft and add chopped fresh tomato and garlic and ginger paste. Cook for another few more minutes until fragrant.
Transfer the ingredients into a blender and add the miso paste and soy sauce. Blend for a minute or two until the mixture becomes a paste.
Transfer the paste back into the pot and add the stock and kombu, previously rinsed.
Reduce heat to low and let it simmer for 20 minutes while you prepare the toppings.
Mix in a separate bowl the sesame oil, sriracha, rice vinegar, maple syrup, soy sauce and garlic powder. This will give our ramen an extra umami kick.
Remove the kombu and put the broth through a strainer, placing another pot underneath.
Add the tahini into the broth, mix well until perfetly dissolved.