Grease the bottom of a 9 x 13 inch casserole dish.
Drain the tomatoes well, reserving the juice. Combine the ketchup with the reserved juice.
Slice the polenta into 24 thin slices.
Slice the hot dogs into thin slices.
Add a few spoonfuls of ketchup on the bottom of the casserole dish. Place 12 of the polenta slices on top.
Put half the diced tomatoes and half the hot dogs on top of the polenta. Sprinkle with about half of the remaining ketchup.
Put a layer of cheese over everything.
Repeat the layers: polenta, hot dogs & tomatoes, ketchup, and cheese. Place the second layer of polenta pretty much over top of where the first layer was so that the slices are above each other. This makes serving easier.
Bake at 350 degrees about 30 minutes until hot through.
Serve by using a spatula to lift out a section of polenta slices.
Recipe by Gluten-Free Homemaker at http://glutenfreehomemaker.com/polenta-hot-dog-casserole/