Turn on the oven to 400 degrees. On a rimmed baking sheet, toss the sunchoke pieces with theolive oil and a generous sprinkling of salt. Slide them into the oven and roast, turning them with a spatula every few minutes, until they are completely tender and beginning to brown, about 45 minutes. Cool.
While the sunchokes are roasting, roast the poblanos (if you’re using them) over an open flame or (when the sunchokes are done) close up under a preheated broiler, turning them until they are blackened and blistered all over, about 5 minutes for an open flame, 10 minutes for the broiler. Cover with a kitchen towel and cool until handleable. Rub off the blackened skin, pull out the stems and seedpods, then briefly rinse to get off stray seeds and bits of skin. Chop into ¼-inch pieces and scrape into a medium bowl. (If you’re using the chopped chipotle chile, scrape it into the bowl.)
Add the sunchokes to the bowl, then measure in the mayonnaise (or one of its stand ins), the green onion, the mojo solids and your herb of choice. Stir everything together. Taste and season with salt (the sour cream and yogurt versions will take at least ¼ teaspoon). I think this salad tastes best when the flavors mingle for an hour or two in the refrigerator.
Riffs on Roasted Sunchoke Salad: Of course, this same delicious salad can be made with roasted fingerling or new potatoes,carrots, sweet potatoes, parsnips, little turnips—pretty much any vegetable you can toss with oil and roast.
Roasted Garlic Mojo
In a large (10-inch) dry skillet, roast 4 heads of garlic (separated into cloves but not peeled) over medium heat, turning regularly until they’re soft and blackened in spots, 10 to 15 minutes. Cool, peel, place in a food processor and pulse until roughly chopped. Turn the machine on and add 2 cupsolive oil in a steady stream. Stop the machine, add ¼ cup lime juice and ½ teaspoon salt and pulse to incorporate. Store refrigerated in a sealed container.