Blend: Add apple, red lentils, and water/broth to a saucepan. Bring to a boil over medium heat and simmer for 15-20 minutes until lentils are very soft. Remove any foam that forms on top. Once lentils are soft, turn off heat and blend with an immersion blender. If you only have a stand blender, let the lentils cool for 5-10 minutes, then add to a blender and blend until smooth.
Mix spices together in a small bowl and set aside.
Heat 1 tbsp oil in a pot over medium heat. Add onions and cook, stirring occasionally, until they start to brown and caramelize (about 10-15 minutes). Add a splash of water as needed if the onions start to stick to the bottom of the pot.
Add carrots, celery, garlic, and ginger. Cook, stirring occasionally, for 3 minutes.
Add spices and stir for 30 seconds. Deglaze the pot with water if needed.
Add tomato paste and stir for 1 minute to darken. Deglaze the pot with more water if needed.
Add water/vegetable broth, cover, and bring to a boil. Reduce heat to medium low to maintain a gentle simmer for 10-15 minutes until the carrots and celery are soft. Check the pot occasionally and add more water/broth if needed. The veggies should be just barely submerged in liquid.
While the vegetables are simmering, pan fry the tofu. Heat remaining 1 tbsp of oil in a pan over medium heat. Add tofu cubes and cook, turning every few minutes to brown each side.
Once the carrots and celery are soft, add the zucchini and mushrooms to the pot and stir to combine. Cover and simmer for 5 minutes. The zucchini and mushrooms will release water as they cook down, but you can add some water if it still looks dry after a couple minutes.
Add the blended lentil mixture, Chuno Sauce, soy sauce, tofu, and MSG. Simmer 5-10 minutes until the zucchini is soft.
Turn off heat. Taste and add salt as needed. You can serve immediately, but curry tastes even better after resting.
Notes
1) Mushrooms: I prefer shimeji, but you can use other varieties of mushroom as well. Sliced white button or baby bella mushrooms would be good.2) Chuno Sauce: This is essentially a kind of Japanese Worcestershire sauce. Bull Dog brand is the most popular, but there are other brands like Kagome and Donki who sell their own versions. You can swap for Japanese Worcestershire Sauce or Tonkatsu Sauce, but check the ingredients as some may contain anchovies/fish extracts. You can also use a vegan Worcestershire sauce and add a teaspoon or two of sugar, maple syrup, or agave.3) Gluten-Free: Use a gluten-free soy sauce or tamari. Also check your Worcestershire sauce to make sure it doesn't contain wheat/gluten (they are usually thickened with starch).