Soak lentils in water at room temperature over night. Drain lentils through a length of cheese cloth, collect the ends to form a 'bag' and hang the lentils over your sink or a bowl for 24 hours. Sprout tails should appear from each lentil. They can be stored in the refrigerator for up to two weeks in a covered container.
In a medium sauce pan, sauté over medium heat, onion, carrot and thyme branches with black pepper. Add garlic and cook. Add vinegar and allow to reduce until almost dry. Add tomatoes and half of the stock. Reduce heat to medium low, and allow to simmer for 10 minutes.
Add the rest of the vegetable stock and the sprouted lentils, stir well, and allow to return to simmer for 2 more minutes, then remove from heat.
Stir in miso and nutritional yeast until well combined to a stew consistency. Adjust seasoning with Umeboshi plum vinegar. Add peas and serve immediately.