In large Dutch oven cook potatoes and onion until tender. Drain all but 1 cup of liquid, keeping it in the pan with potatoes and onion. In saucepan, melt butter and stir in flour and salt and pepper. Add the flour mixture to the potato mixture. Cook and stir until mixture thickens and starts to bubble. Add milk, ham, cheese, and creamed corn. Stir over low heat until the cheese melts. SERVES 6