Spread the diced vegetables on a baking pan or roasting pan and drizzle with just enough oil to coat when you toss them. Sprinkle on a little coarse salt. Bake at 350 degrees until almost tender.Meanwhile, saute the leeks and garlic in a large soup pot in just enough oil to coat the pan. Add the vegetable broth and apple cider vinegar and simmer 5 minutes. Add the roasted vegetables and bring to a simmer.Turn off the heat. Mix a little hot broth in with the miso and break up clumps with a fork or chopsticks. Stir this mixture into the stew. Do not heat again once miso is added as it will ruin the health benefits of the miso. Add water if needed. It should be a thick, chunky stew with a little broth. Serve topped with a spoonful of pistachios.