Place cooked and cooled macaroni in a large mixing bowl. Add the pearl onions.
In a 1 qt saucepan combine Campbell’s® Fiesta Nacho Cheese Soup and one can of milk, and add 3 tbls of butter. Whisk together until well combined while heating over medium heat, about 5 minutes. Remove from heat. Pour the soup mixture over the macaroni and onions, add the Pace® Picante Sauce, salt and pepper to taste, and stir to combine well.
Preheat your oven to 350°. Using the remaining 1 tbls of butter, prepare a 2 qt baking dish by buttering the inside surface well. Pour the macaroni mixture into the baking dish, cover with foil, and bake in the oven for 30 minutes.
*STAR INGREDIENT: Fresh Pearl Onions. To peel fresh pearl onions, simply plunge the onions into boiling water for 1 minute, and then remove from the water. The skins will loosen, making them easy to peel once the root end is trimmed off.