Have a game plan. Pick 3-4 ideas from this list and rotate through them during the week. Build a freezer stash. I encourage you to gradually build up your freezer stash by doubling a recipe once or twice a week. Prep the produce in advance.
Instead of just cereal and milk, may I suggest a breakfast cereal bar with an assortment of toppings? It will make the whole experience so much more fun, and your child will love having complete autonomy in picking and choosing what goes in their cereal.
Sure you can serve plain yogurt BUT, just like with cereal, by switching up the toppings, you can easily invite variety into your child's breakfast or snack!
Cookies first thing in the morning? You bet ya! Serve with protein/fat (eggs, yogurt, cheese, or milk) and a fruit/vegetable.