Tip #1: Do not overmix
If I could narrow it all down to just one important rule in baking muffins, it would have to be not to overmix. Muffins are said to be the easiest bake, but all it takes is just some extra flicks of the whisk, and you’ve got yourself the driest bake. When incorporating the wet ingredients into the dry, there is a tendency to overmix because the ratio of liquid to flour is quite high. Mixing too much develops the gluten in the flour, which results in hard and dry muffins with ‘tunnels’.
You simply need to mix the ingredients just until the flour is sufficiently moistened. Some bakers recommend mixing no more than 15 strokes, but personally, a good sign to stop before you overmix is when all the flour is off the bottom of the bowl, and you still see some flecks of flour in the mixture. This is definitely not one of those moments you’d want to exercise your OCD tendencies;– the batter should be lumpy, never smooth!
Tip #2: Fill them up just enough
It is undeniable that what makes muffins so appealing is the appearance, more specifically their trademark muffin top. But this is where it gets really tricky when it comes to baking your own muffins, hoping to get the ‘bakery muffin dome’. Fill the muffin cups too little, and you’ll get flat tops or shrunken muffins. Fill the muffin cups too much, and you’ll get ‘flying saucer’ tops.
Be generous, but not overly so. Scoop the batter into each muffin cup, filling it to 3/4 full and try to mount more batter in the middle of each cup. This ensures that the resulting muffins will have a nice dome.
Tip #3: Letting the batter sit — yes and no
As with any bake that contains leavening agents, you would want to go straight from the counter into the hot oven as soon as possible. Since the rising factor is one of the primary characteristics of muffins, leaving the batter outside (of the oven) will affect not only the appearance, but also its texture. However, this differs with different recipes, and more specifically, different leavening agents.
For recipes that call for baking powder, you may allow the batter to sit for 5-10 minutes before going into the oven. Single-acting baking powder reacts with the liquids in the batter at room temperature to create air bubbles that will help in the rising. Double-action baking powder reacts in two phases;– some gas is released at room temperature upon mixing with the liquids, while most of the gas is released at high temperature upon baking.
For recipes that call for baking soda, you would want to rush the batter straight into the hot oven. Baking soda reacts with the acids in the batter (typically yoghurt, buttermilk) to create bubbles of carbon dioxide that expand under the high baking temperature. These bubbles are created immediately upon mixing, so you should not leave the batter sitting out, lest the chemical reaction stops before you get them to the oven.