Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners.
Combine flour, pumpkin spice, baking soda, and salt in medium bowl. Mix and set aside.
Coarsely grate zucchini, skin on. Measure out 1 cup. For best results, place grated zucchini on a cutting board and coarsley chop into small pieces. This way there are little flecks of zucchini throughout the muffins. Place zucchini in the center of a clean dishcloth or a stack of paper towels. Squeeze well to remove moisture, as zucchinis have a high water content. Set aside.
Combine pumpkin puree, sugar, egg, oil, and juice in a large mixing bowl. Whisk until blended.
Add flour mixture to pumpkin mixture and stir with a fork or whisk until just moistened. Fold in zucchini.
Spoon batter into prepared muffin cups. For a domed top we're filling them about 3/4 of the way full.
Bake in preheated oven for 35-40 minutes, checking for doneness with a toothpick inserted to the center of the cupcake. I bake at sea level (if this helps) and oven times will vary a bit, as they tend to do.
Allow a few minutes to cool then carefully remove muffins from muffin tin. Allow to cool completely on a wire baking rack before diving in. (Flavors will be more pronounced once fully cooled.) Enjoy!
Notes
Feeling fancy? you can totally sprinkle some mini chocolate chips into the batter if desired. You can even go for a cupcake vibe and frost these muffins with cream cheese frosting. I'll toss the recipe in the blog post for ya!Nutrition Facts below are estimated using an online recipe nutrition calculator. Adjust as needed and enjoy!