Soggy muffins are a sad sight—and taste! Use the power of salt to keep your zucchini muffins light and fluffy (but not salty).
Adjust oven rack to middle position and heat oven to 325 degrees. Spray 12-cup muffin tin, including top, with vegetable oil spray.
In medium bowl, whisk together whole-wheat flour, all‑purpose flour, cinnamon, baking powder, baking soda, nutmeg, and remaining 1 teaspoon salt.
In now-empty large bowl, whisk together eggs, oil, vanilla, and 1 cup sugar. Add zucchini and use rubber spatula to stir until combined.
Place muffin tin in oven. Bake until muffins are golden brown and toothpick inserted into center of 1 muffin comes out clean, 25 to 30 minutes.
Use oven mitts to remove muffin tin from oven (ask an adult for help). Place muffin tin on cooling rack and let muffins cool in tin for 15 minutes.
Vegetables and fruits such as zucchini (surprise—a zucchini is technically a fruit!) are mostly made up of water. A big challenge when you’re cooking or baking with them is dealing with all that water—no one likes a watery stir-fry or a soggy muffin! One of salt’s many superpowers is that it can pull water out of food. Plants (and animals) are made up of countless tiny cells. When you sprinkle salt on plants like zucchini, some of the water inside the cells is pulled out toward the salt. This process is called osmosis (“oz-MOE-sis”).
Squeezing the shredded zucchini in a towel gets some of the water out, but salting even half the zucchini and letting osmosis do its work lets you squeeze out at least double the water. This is especially helpful when you’re using zucchini, because about 95 percent of a zucchini is actually water! What happens if you don’t salt any of the zucchini? You’ll wind up with more water in your muffin batter, which will bake into soggy, squat muffins.