In batches in a food processor, puree the avocados, chicken stock, green onions, lemon juice, cilantro, 1 teaspoon of the salt and the cayenne. Pour into a soup tureen or large pitcher and stir in the heavy cream just before serving.
In a small skillet, heat the oil over medium-high heat. Add the corn kernels, cumin and remaining 1/2 teaspoon salt, and cook until fragrant and golden brown, about 5 minutes, stirring occasionally. Remove from the heat and garnish each serving of soup with 2 tablespoons of the toasted corn and 1 sprig of cilantro.
Yield: 4 to 6 servings