Batters
The bread-like muffin batter is made using the "muffin method". This batter can be assembled and baked 'quickly', usually in 20-25 minutes. Only two bowls are needed to make the batter. One bowl is used to mix all the dry ingredients together. The second bowl contains all the wet ingredients. The fat used with the bread-like muffin is usually in liquid form, either an oil or melted butter. Then the wet and dry ingredients can be mixed together. The important step here is not to overmix the batter. However, there is a tendency to over mix because the ratio of liquid to flour is quite high. But mixing too much overdevelops the gluten in the flour which will cause a tough muffin with tunnels and a compact texture. Only 10 to 15 strokes are needed to moisten the ingredients and the batter should be still lumpy and you may still see a few traces of flour. Don't worry about these lumps as the batter continues to blend as it bakes and any lumps will disappear. Note: Over mixing the muffin batter causes it to become very stringy. This is the gluten developing in the flour. Over mixing causes long strands of gluten to form making it hard for the leaveners to work and causes long tunnels in the baked good.
The cake-like muffin batter is prepared using the same method as making a cake batter. The butter (room-temperature) and sugar are creamed together. The eggs are mixed in and then the wet and dry ingredients are added alternately. The higher sugar and fat content in this type of muffin act as tenderizers thereby producing a richer cake-like muffin with a softer crumb. The increased fat content also minimizes the development of gluten which again helps to produce a muffin with a softer crumb.
Banana Muffins Recipe Demonstration - Joyofbaking.com