Heat oven to 500 F. Place the corn kernels on a baking sheet. Roast in the oven until they begin to caramelize, about 8 minutes.
In a large soup pot, heat the oil over medium-high heat. Add the onion, carrots, celery and garlic, stirring constantly. Cook until the vegetables are soft and tender, about 5 minutes. Reduce heat and stir in the corn, flour and cumin. Mix until the flour is evenly dispersed.
Add the vegetable stock and jalapenos and let simmer for about 30 minutes. Stir in half-and-half, salt, pepper and parsley. Remove from heat and serve.