Creamy Squash Soup with Corn Salsa and Wild Onion Chimichurri

To make the chimichurri, on a grill or in a very hot, dry cast-iron skillet over high heat, cook the wild onions until nicely charred in some spots but not totally blackened. Coarsely chop the charred onions and add them to a blender or food processor with the parsley, vinegar, maple syrup, salt, and oil. Puree the mixture until it reaches a slightly chunky, pesto-like consistency. To make the soup, cook the ears of corn on a grill, turning occasionally, until they are lightly charred on all sides. Remove the corn from the heat and set it aside to cool. Add the oil to a large (5- to 7-quart) Dutch oven or stockpot and heat over medium heat. Add the yellow onion and garlic. Cook, stirring frequently, until the onion and garlic have caramelized and turned a light golden brown. Cut the corn from the cobs, reserving the cobs for the soup and the kernels for the salsa. Put the cobs in the pot with the sauteed onion and garlic. Add the water to the pot, place it over high heat, and bring it to a boil. Reduce the heat to a simmer (if cooking over a fire, move the pot to a cooler spot on the grill to maintain a simmer). Allow the mixture to simmer for 15 to 20 minutes, until the broth becomes fragrant with the aroma of sweet corn and the liquid has reduced to about 4 cups. Add the cubed squash, bring the liquid back to a simmer, and cook until the squash is very tender. Working in batches, use an immersion blender or a countertop blender (allow to cool slightly before putting into blender) to puree the soup until smooth. Season with salt and black pepper to taste. To make the salsa, combine the reserved corn kernels with the jalapeño and stir to mix well. Season with salt and pepper to taste. To serve, ladle the soup into bowls, garnish with a generous scoop of the roasted corn salsa, and drizzle with the wild onion chimichurri.