Cut the stems off the cabbage heads and then cut each one in half, then in half again.
Place the cabbage steaks on a baking sheet that is lined with parchment paper. Season the cabbage steaks with salt, pepper, and garlic powder.
Spread a spoonful or two of mayo on top, generously covering the cabbage steak.
Add some ketchup and spread it as well, allowing the ketchup to mix with the mayo.