In a large bowl, whisk together flour, granulated sugar, brown sugar, baking soda, baking powder, cinnamon, pumpkin spice, and salt. This ensures the spices are evenly distributed and prevents clumps.

In another bowl, whisk pumpkin puree, eggs, oil, milk, and vanilla until smooth. Pumpkin puree acts as both a flavor booster and a natural moisture enhancer.

Pour the wet mixture into the dry ingredients. Gently fold using a spatula until just combined—do not overmix. A few lumps in the batter are perfectly fine and help keep the muffins tender.

Line a muffin tin with liners or grease it well. Divide the batter evenly among the 12 cups, filling about ¾ full.

Bake at 350°F (175°C) for 18–22 minutes. Insert a toothpick into the center—if it comes out clean, the muffins are ready. Let them cool for 5–10 minutes.

In a small bowl, mix cinnamon and sugar. Brush the tops of the warm muffins with melted butter. Roll or sprinkle each muffin generously in the cinnamon sugar mixture.

This step gives the muffins their signature bakery-style flavor and texture.