A basic plain muffin recipe and a quick bread recipe can be interchangeable. That is, as far as the ingredients go. The main variables that will require a little tweaking are cooking times and temperatures. That, and you need to make sure you have a good loaf pan or muffin pan.
This means is that if you have a favorite muffin recipe that you would love to convert into a quick bread (or vice versa), you can. Your treasured quick bread can become muffins in less than half the time it takes to make the quick bread.
The Quickness in Quick Bread
Compared to yeast bread, quick bread is really quick. That is because quick breads are made with baking powder, a fast-acting chemical leavening agent that produces carbonated gas when combined with liquid, which is what causes the batter to bubble up and rise. Once you combine the liquid and dry ingredients, you want to get the batter into the pan and in the oven fast, or else the gas will expend itself before the heat of the oven has a chance to set the glutens in the flour.
A loaf is a far less "quick" form of quick bread because loaves take longer to bake. On the other hand, filling 12 muffin cups is considerably more tedious than simply pouring all the batter into a loaf pan. Not to mention the fact that it is nearly impossible to spoon the exact amount of batter into each muffin cup without dripping batter all over the place, especially on the edges of the pan where it will burn and smoke if you do not wipe it off first. And remember, you need to hurry so that the baking powder does not exhaust itself prematurely.
Do Not Rush
Although it sounds like you need to worry about rushing, think about pancake batter for a minute. The secret to making pancakes (a runnier, quick bread) is letting the batter rest for 15 to 20 minutes before cooking. Although, you are supposed to be in a hurry, the reason for resting pancake batter is that you do not want to mix the batter until every last lump is gone because doing so will overwork the glutens and make your pancakes rubbery. Resting the batter allows the lumps of dry flour to dissolve on their own.
Overmixing is also the bane of muffins and quick bread. And when you consider that spooning batter into muffin cups requires dragging a spoon through the batter, which is no different than stirring it, you can understand why it is so important to use the fewest possible strokes when you mix the ingredients.
What about losing the expendable gases as time drags on? Store-bought baking powder is almost always "double-acting," which means that it releases an initial burst of gas when it is combined with liquid, and then a second burst that is triggered by heat.
So, it is true that a certain amount of carbonated gas will be expended when the wet and dry ingredients come together, resting the batter does not affect the second burst of gas that happens in the oven. The only caveat here is that if you should happen to make your own baking powder, the homemade type will not be double-acting. It is going to produce all its gas as soon as you combine the ingredients.
The important point here is that if 15 to 20 minutes of resting is not going to spoil your pancake batter, you can certainly afford to take your time spooning the batter into your muffin cups. Panicked spooning is messy spooning.
Filling Your Pans
There is a fine art to filling muffin and loaf pans. The great secret: fill the muffin cup or loaf pan about 3/4 of the way full. Generally speaking, this technique will work for recipes where there is about 260 grams of flour or approximately 2 cups.
Save yourself some time and elbow grease by using paper muffin liners. And, you might want to line your loaf pan with parchment paper. Life is far too short to waste any precious time prying and scouring quick bread or muffins out of pans (not to mention eating the mangled results).
Converting From Muffins to Quick Bread
The main difference between muffins and quick bread is that muffins take significantly less time to cook. So if you are converting muffins to a loaf, check the temperature of your muffin recipe. If it calls for 375 F, you will want to lower it to 350 F.
And you will want to increase the cooking time to at least 45 minutes, possibly longer, depending on factors including whether the batter includes wet ingredients like blueberries, how accurate your oven temperature is, the size of your pan, and even what color it is.
They key here is to test for doneness by inserting a toothpick into the center of the loaf. If it comes out clean, it is done.
Converting From Quick Bread to Muffins
Unsurprisingly, converting the other way is going to involve increasing the temperature, and decreasing the cooking time. If your quick bread recipe bakes at 350 F for 60 minutes, try bumping it up to 375 for 30 minutes, or even 400 F for 20 minutes. Again, use the toothpick test at around 15 to 20 minutes, and keep an eye on the muffins. Once the muffins start looking golden brown on top, you should definitely check them with a toothpick.