Taqueria del Sol?s Poblano Corn Chowder

"In a small bowl, make a roux by mixing 1/2 cup margarine and flour together until thoroughly combined. Set aside.In the bowl of a food processor, puree onion and celery. Drain off any liquid and reserve solids.In a large stockpot, melt the remaining 2 tablespoons margarine over medium heat. Add onion-celery puree and poblano pepper pieces. Cook until vegetables soften but do not brown, about 10 minutes. Add cream, half-and-half, shrimp, sugar, lobster base, black pepper and chile de arbol. Bring to a simmer and add roux. Simmer three minutes or just until shrimp is cooked through. Add whole corn and creamed corn and taste for seasoning, adding salt or sugar if necessary."