Clam-and-Corn Chowder

In a small saucepan over medium-low heat, bring the diced potatoes and water to a boil to coat. Cook until tender, about 10 minutes. Set aside. From 3 cobs of corn, cut out the kernels; leave the cobs. Preheat the grill to medium heat (350 ° F to 400 ° F). Saute the remaining 2 cobs of corn under the lid until browned, about 8 minutes, turning frequently. Cool for 5 minutes; remove the seeds from the grilled corn and discard the roasted cobs.Heat the oil in a large saucepan over medium-high heat. Add the onion, shallots, garlic and sugar and cook, stirring frequently, until soft and fragrant, about 5 minutes. Add the butter and raw corn kernels and cook until the corn is tender, about 10 minutes. Pour in the wine and cook for 1 minute.Add cream, seafood broth, salt, cayenne pepper, reserved raw cobs, jalapeno halves, thyme and rosemary sprigs. Turn up the heat to high and bring to a boil. Reduce the heat to medium-low and cook until the liquid is reduced by a third, 15 to 20 minutes. Remove and discard the thyme, rosemary, corn cobs, and jalapeno halves.Transfer the mixture to a blender. Remove the center part of the blender lid (to release steam); secure the lid to the blender and cover the hole in the lid with a clean towel. Beat the mixture until smooth, about 30 seconds. Return the mixture to the pan. Add the roasted corn kernels, boiled clam meat, boiled potatoes, and raw clams in shells. Cover and cook over medium-low heat until the clams are uncovered, about 5 minutes. Remove the uncovered clams; divide into 4 plates.Place the chowder on top of the clams and sprinkle with herbs. Serve with lemon wedges.