2 tablespoons olive oil
1 medium onion, coarsely chopped
1/4 cup finely chopped fresh cilantro stems
2 garlic cloves, coarsely chopped
1 (2 1/4-pound) piece calabaza squash or 1 (2 1/2-pound) whole kabocha squash, peeled, seeded, and cut into 1/2-inch pieces (6 cups)
4 cups water
1 1/4 cups well-stirred canned unsweetened coconut milk (12 ounces)
3 ears of corn (fresh or thawed frozen), kernels cut off and reserved for relish (below) and cobs halved crosswise
2 teaspoons salt
1/4 teaspoon cayenne
4 1/2 teaspoons fresh lime juice
1/4 teaspoon salt
Pinch of sugar
2 tablespoons olive oil
2 cups corn kernels (see above)
2 tablespoons coarsely chopped fresh cilantro
1 tablespoon finely chopped shallot