01 - Set oven to 350°F. Line a muffin tin with twelve paper liners or grease thoroughly.
02 - Whisk all-purpose flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger in a medium mixing bowl until evenly blended.
03 - In a large bowl, whisk together pumpkin purée, granulated sugar, brown sugar, eggs, vegetable oil, milk, and vanilla until fully incorporated and smooth.
04 - Gently fold dry mixture into wet batter using a spatula until just combined. Avoid overmixing.
05 - Portion batter evenly into prepared muffin tin, filling each cavity approximately three-quarters full.
06 - In a small bowl, combine crushed salted pretzels, brown sugar, and melted unsalted butter. Stir until thoroughly coated.
07 - Sprinkle pretzel crumb mixture generously atop each filled muffin.
08 - Transfer muffin tin to the oven and bake for 20 to 22 minutes, or until a toothpick inserted into the center emerges clean.
09 - Let muffins rest in the pan for 5 minutes, then remove and transfer to a wire rack to cool completely.