One of our favorites, from way way back, are stuffed muffins. Basically, these are corn muffins, with added cheese, meats or veggies, then baked. Very easy, and a typical batch makes at least 12, so you can freeze the extras. There are two basic options--make corn muffin mix (my recipe is here) or use a boxed mix like Jif. Make the corn muffin batter, then add several cups of extras to it. You want to see lots of the extras in the batter, not mostly corn muffin batter. Bake per your recipe or package directions.
Today, the kids had ham and cheese muffins (a packet of diced ham and several handfuls of shredded cheese), along with carrots & hummus, strawberries, and creme brûlée crisps.
Two other favorite stuffed muffins:
F&B also like corn dog muffins--dice up hot dogs, add those and shredded cheese to the cornbread batter.