Preheat oven to 375°. Spray a 12-cup muffin pan with cooking spray.
In a large bowl, whisk together milk, sour cream, and egg, until smooth.
In another bowl, whisk together flour, cornmeal, corn, sugar, and baking powder. Add milk mixture to flour mixture, stirring until just combined. While stirring constantly, add melted butter in a slow and steady stream until just combined. Fold in cheese and ham. Divide batter between prepared muffin cups.
Bake until golden brown and a wooden pick inserted into center comes out clean, 15 to 20 minutes. Let cool in pans 10 minutes. Remove from pan. Serve warm.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/ham-and-cheddar-corn-muffins/