Use sourdough discard to make these soft and delicious zucchini muffins! They're full of whole grains, using spelt and oat flours, and have a nutty crunch from chopped walnuts.
In a medium bowl, stir together spelt flour, oat flour, cornstarch, baking soda, cinnamon, and salt. In a separate bowl, whisk together honey, sugar, sourdough starter, bananas, zucchini, egg, olive oil, and vanilla.
Pour wet ingredients into dry, then gently stir to combine, until no flour streaks remain. Fold in walnuts.
Liberally grease muffin holes or fill with paper lines. Fill muffin cups 3/4 full. Sprinkle with demerara (coarse) sugar. Bake for 20 minutes, until toothpick comes out with a few crumbs but batter is not wet. Let cool for one hour before eating.