Michael Ruhlman's Ratio defines a muffin as a form of a quick bread. The basic quick bread ratio is:
- 2 parts flour
- 2 parts liquid
- 1 part egg
- 1 part fat
So you can make a muffin with those basic ingredients in about that ratio. Remove any of those ingredients, and you no longer have a muffin. Substantially change those ingredients, and you've moved somewhere else in the dough continuum or even towards a batter.
Personally I'd classify a cupcake as a type of cake. The ratio for pound and sponge cake are both:
- 1 part butter
- 1 part sugar
- 1 part egg
- 1 part flour
The differences between cakes are often the mixing method - creaming versus foaming, for example. You can see, though, that in a muffin your flour-to-fat ratio is higher than in a cake. Muffins also don't require sugars. Cakes and cupcakes do.
From the basic quick bread ratio, you should be able to add any fruit or other ingredients (try bacon or turkey bacon), substitute in dry ingredients for flour such as bran or oatmeal (or another grain), and make a lot of other interesting changes. Just make sure you stick to the basic proportion of a quick bread. If you add a very wet ingredient, remove some liquid. Change tastes by adjusting oil versus butter (or browning your butter). Add sugar, baking powder or soda for leavening, spices, extracts, etc.
This table comes from the front of the muffin section in Bread, by Beth Hensperger:
Muffin size Baking time Yield
Mini/gem (1 5/8") 10-15 minutes 18-20
Regular (2 3/4") 20-25 minutes 9-10
Oversized (3 1/4") 25-30 minutes 6-7
Muffin cake (8-9") 55-65 minutes 1
The baking times are for 375-400°F; most recipes will fall around that range. Note that the yields don't necessarily match up to typical pan sizes; for example, if you take a recipe meant for 12 regular muffins, you'll probably have more batter than you need for a pan of 6 oversized muffins. Perhaps this is your problem - you could be overfilling. If even after scaling the volumes appropriately, you still have problems, you could try reducing the temperature by 25°F and increasing the baking time.
("Muffin cake" refers to baking in an 8-9" pan of some sort - the author says that you can get away with it for any muffin recipe, but I've never tried it!)
Best Answer
Most of the bake times that recipes give you are very general ideas of how long you should bake something. This is why most of them are given in ranges rather than in specific values. (20-25 minutes instead of specifically saying 21 minutes)
The reason for this is because there are a lot of variables when it comes to baking including the thickness and material of your pan and the type of oven you have.
The best thing to do when you are trying to bake batter for muffin/cupcake in a cake pan is to start out with the initial time the recipe gives you and then there after, check it periodically with a toothpick in the center. If the batter sticks to the toothpick then it is not done. You can check it every 5 minutes to start off but as the "cake" start to stick less to the toothpick, check more often.