Heat a Dutch oven or large oven-safe pot over medium heat and add the oil. Once hot, add the jalapeños and sauté for 1-2 minutes, just slightly softened.
Add the butter and let it melt, then add the flour. Whisk and cook for 2 minutes.
Pour in the cream, milk, salt, pepper, and sugar. Bring the mixture to a gentle boil, stirring frequently.
Add the corn and gently stir to combine. Return the mixture to a boil and cook for 1-2 minutes until thickened, stirring constantly to avoid burning.
Sprinkle on the Parmesan cheese.
Bake, uncovered, for 20-25 minutes or until hot and bubbly throughout. It will thicken more as it cools. Serve hot, garnished with breadcrumbs.