Preheat the oven to 425 degrees Fahrenheit and position the rack in the center for even heat distribution, then line a standard 12-cup muffin pan with paper liners.

Whisk the all purpose flour, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger together inside a large bowl until completely uniform with no visible spice clumps.

In a separate large bowl, whisk the pumpkin puree, granulated sugar, brown sugar, vegetable oil, and room-temperature eggs together vigorously for one minute until smooth, glossy, and deep orange.

Fold the dry flour mixture into the wet pumpkin mixture gently using a silicone spatula with broad sweeping motions, stopping as soon as no flour streaks remain after 10-15 strokes maximum.

Let the thick batter rest at room temperature for ten minutes to allow the flour starches to hydrate fully for improved texture.

While the batter rests, beat the softened brick cream cheese, powdered sugar, and whole milk together using a mixer on medium-high speed for two to three minutes until completely smooth, fluffy, and pale.

Transfer the cream cheese filling mixture into a pastry piping bag or zip-top bag with one corner snipped, then tap firmly on the counter to release trapped air bubbles.

Divide the rested pumpkin muffin batter evenly among the twelve lined cups, filling each about three-quarters full using a large cookie scoop for uniform portions.

Insert the tip of the piping bag into the center of each batter cup, pushing down about halfway, then gently squeeze to inject one to two tablespoons of cream cheese filling.

Sprinkle the surface of each unbaked muffin generously with coarse demerara sugar and raw green pepitas, pressing down gently so the toppings adhere.

Place the pan in the preheated 425-degree oven and bake for exactly five minutes without opening the door to trigger rapid steam production and dramatic rise.

Lower the oven temperature to 350 degrees Fahrenheit without opening the door and continue baking for fifteen to eighteen additional minutes until deeply golden and a toothpick inserted into the cake portion comes out clean.

Remove the pan from the oven and let muffins cool in the pan for five minutes, then transfer to a wire cooling rack to cool completely before serving.