Prep the Oven and Pan: Start by heating your oven to 375°F. Line a muffin pan with paper liners or lightly grease each cup. This helps the muffins release easily once baked.
Mix the Dry Ingredients: In a large bowl, whisk together the flour, baking powder, salt, and brown sugar. Break up any sugar clumps so the batter mixes smoothly later.
Combine the Wet Ingredients: In another bowl, mix melted butter, milk, egg, vanilla, and pumpkin until smooth. The mixture should look creamy and evenly blended.
Add the Zucchini: Grate the zucchini and gently squeeze out extra moisture using a paper towel. Stir it into the wet mixture so it spreads evenly.
Bring the Batter Together: Pour the wet mixture into the dry ingredients. Stir gently until just combined. Stop mixing once you no longer see dry flour. Overmixing can make muffins dense.
Fill the Muffin Cups: Spoon the batter evenly into the muffin pan, filling each cup about three quarters full. Sprinkle pepitas and turbinado sugar on top for crunch.
Bake Until Golden: Bake for 20 to 24 minutes until the tops look set and a toothpick comes out clean. Let muffins cool in the pan for a few minutes before moving to a rack.
