Preheat oven to 350 degrees. In a large Dutch oven, add 2 tablespoons butter and sauté the onions, bell pepper, and garlic until slightly tender and fragrant. Add the frozen peas and carrots, stirring to combine.
Add flour and stir until well blended. Add the milk and cream of chicken soup, stirring to blend all ingredients together.
Add the ham to the filling mixture, stirring to combine. Pour filling into a greased 9x13-inch casserole dish.
Line canned biscuits on top of filling mixture. Brush tops of biscuits with 2 tablespoons melted butter and bake for 20 to 30 minutes at 350 degrees, or until biscuits are golden brown.
Cooking Time: Watch the cooking time carefully! Do not use the cooking time included with the canned biscuit instructions. Because this dish bakes at a lower temperature, the biscuits will take longer to cook than instructed on the can.