For extra flavor and texture, add 1/4 cup of chopped walnuts or pecans to the batter. To ensure the zucchini doesn't make the muffins soggy, squeeze out any excess moisture after grating it. These muffins freeze well! Store them in an airtight container for up to 2 months. Feel free to substitute other grated vegetables like sweet potato or butternut squash. For a sweeter muffin, increase the maple syrup to 1/3 cup.