Melt butter in a Dutch oven over medium heat; add ham and onion, and sauté 3 to 5 minutes or until onion is tender. Stir in black-eyed peas and next 3 ingredients. Cover, reduce heat to low, and cook, stirring occasionally, 15 minutes. Remove from heat, and stir in cilantro. Serve immediately over White Cheddar Cheese Grits.