Preheat oven to 350°F. and line a 12-cup muffin tin with parchment paper liners or silicone liners.
Grate the zucchini, toss with a sprinkle of salt and let it stand in a colander set over a bowl to drain.
Melt the butter and set it aside to cool.
Chop the green onions (scallions) and grate the cheese.
In a medium bowl, whisk the dry ingredients together.
In a large bowl, combine the eggs, buttermilk, and melted and cooled butter.
Add the dry ingredients to the wet ingredients and stir until combined.
Stir in the green onions (scallions) and ¾ cup of the grated cheese.
Squeeze as much water as you can from the shredded zucchini, using a clean teatowel or cheesecloth or even your hands. Gently fold it in to the muffin batter.
Divide the batter among 12 muffin tins. Top each muffin with a small amount of the remaining ¼ cup of cheese, dividing it equally among the muffins.
Bake at 350°F. for 22 - 26 minutes or until a toothpick inserted comes out clean or with just a few crumbs.
Let the muffins sit in the muffin tin for 10 minutes, then remove to a wire rack to cool completely.
Make your own buttermilk substitute by adding ¾ tablespoon lemon juice or vinegar to ¾ cup of milk or plant-based milk.Use parchment paper muffin liners or silicone muffin cups to bake these zucchini cheddar muffins. The cheese will stick to regular white paper muffin cups making the muffins difficult to remove.Reserve ¼ cup of the grated cheese to add to the top of the muffins before baking.These muffins don't rise with lovely domed tops! Expect them to sink a little after baking.