In a large stockpot, melt butter over medium heat and saute onions until translucent, about 5 minutes. Add potatoes, 1 teaspoon of salt, and saffron. Saute for 1 minute. Increase heat to high and add Corn Broth. Bring to a boil, cover, and reduce to a simmer. Cook for 15 minutes. Add scampi, corn kernels, and tomatoes. Cover and cook for another 5 minutes. Season with 1 tablespoon of salt.
Garnish with basil and 2 Garlic Croutons.
Corn Broth:
Cut the kernels off 2 of the corn cobs and reserve for later. Grate the kernels off the remaining cobs, making sure to keep all the corn milk. Cut all 8 cobs into smaller pieces, about 2 inches long. Place corn milk, cobs, salt and water in a saucepan. Bring to a boil, reduce heat and simmer for 30 minutes. Strain broth and reserve.
Garlic Croutons:
Toast the slices of French bread and rub each piece with the garlic cloves. Butter the toast and set aside.