Start by heading a medium sized pot on medium heat. Add in the butter and let it melt until it comes to a bubble. Next, toss in the flour, and stir with a wooden spoon so that all of the butter soaks up the flour. Continue to stir for a couple of minutes to cook out the flour. Don’t let it get too dark, just a light golden, if any color at all. Now add in the milk and continue to stir. Keep stirring until the sauce thickens. This is your standard bechamel sauce. Once the sauce thickens, add in the cream cheese and cheddar cheese, as well as the garlic salt. Lower the heat, and stir until all the cheese is melted, and you have a smooth consistency.
Preheat your oven to 350 degrees.
To a large mixing bowl, add in the corn, the cubed ham, black pepper, banana peppers, roasted garlic, and tomato. Mix to combine everything. Next, pour in the cheese sauce, and continue to stir until everything is nice and coated.
Add the mixture to your casserole dish, top with the bread crumbs. Place into the oven and cook for about 30 minutes, uncovered. The top should be nice and golden brown, and the casserole itself should be a bit bubbly. Carefully remove, and get ready to dig in.