1 tablespoon olive oil
1 tablespoon butter
1 1/2 cups chopped onion
1 1/2 tablespoons minced peeled fresh ginger
1 1/2 tablespoons minced garlic
1 tablespoon red curry paste
8 cups chopped peeled butternut squash
3 cups unsalted chicken stock
1 cup chopped peeled baking potato
2 teaspoons brown sugar
1 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
2 tablespoons fresh lime juice
1 (13.5-ounce) can light coconut milk
2 tablespoons coarsely chopped fresh cilantro