Melt 3 tablespoons butter in heavy large saucepan over low heat. Add flour and stir 3 minutes. Mix in stock and cream. Increase heat and bring to boil, stirring constantly. Reduce heat and simmer until thickened, stirring occasionally, about 10 minutes.
Meanwhile, melt 2 tablespoons butter in heavy small skillet over low heat. Add onion, carrot and green pepper. Cook until soft, stirring occasionally about 8 minutes. Mix in jalapeños. Add both cheeses to cream mixture and stir until melted. Mix in vegetables. Season with salt and serve.Servings: 8