Melt soup butter in a wide 6-quart pot over medium heat. Cook onion and red pepper for 7 minutes, then stir in the tablespoon soup flour for 1 minute.
Gradually stir in broth, then add corn, ham and pepper. Bring to a simmer and cook for 10 minutes until the vegetables are tender and the ham reaches 165°F.
Stir in the cup of soup milk and return to a gentle simmer. Mix dumpling flour, cornmeal, baking powder and salt in a bowl, then rub in the cold butter until small crumbs form.
Stir the separate 1/2 cup dumpling milk into the dry mixture just until a soft dough forms. Use two spoons to drop twelve equal small mounds over the simmering soup, spacing them apart.
Cover tightly and simmer gently for 14 to 16 minutes without lifting the lid. Split one dumpling to check that the center is fluffy with no wet dough; cover and cook for 2 minutes more if needed.
Rest off heat for 3 minutes. Divide chowder among six bowls and add two dumplings to each portion.