I used to make muffins very rarely, due to the fact that my choices were: a. buy disposable muffin cup liners (what, ME pay money for something I'm going to throw away??) or b. scrub a muffin pan when I'm done (yuck). Then one day it hit me: why do muffins have to be round? Since then I've been making them more often, but I just bake a standard dozen-or-so muffin recipe in a 13x9 pan. It works well because you can cut just as much as you want, and cleanup is easier.
Here is a recipe for basic muffins I've been tweaking for a while:
2 cups unsifted flour (I normally use part white, part whole wheat, but suit yourself. You can even substitute oats for 1 cup of flour)
About 1/2 cup sugar (to your taste)
1 tablespoon baking powder
1 teaspoon salt
Mix the dry stuff together.
The liquid part is a little tricky: Take a 2-cup measuring cup. Put in 1 cup of milk and 1 egg. Add oil until the mixture totals 1 3/4 cup. Whisk the liquid stuff well. Then dump it into the dry stuff and stir just until mixed.
Then you can add about a cup of any kind of fruit you want - this morning it was blueberries from the freezer, thanks to my very gracious friend Cami. Also works with drained pineapple, mashed banana, or whatever you like. Or for chocolate chip muffins, add a capful of vanilla and 2/3 cup of chocolate chips. The kids at church are still talking about those.
Then pour into a greased 13 x 9 pan (or muffin pan, if you must) and bake at 425 for 20-25 minutes.
I was going to post a photo of the ones I made this morning, but I forgot to add the baking powder. They ain't pretty. Be sure not to do that if you make them.
Okaaaaay, here's the photo, in case you need a good laugh today: