Combine gingersnaps, brown sugar, and ginger in a food processor, and process until the cookies are fine crumbs. Add butter. Pulse until combined. Press mixture into a 9-inch pie tin. Bake at 350 for 10-12 minutes. Allow to cool before filling.

Rinse pumpkin to remove any dirt or residue. Slice off the stem, then cut pumpkin into quarters. Scoop out fiber, reserving seeds for toasting. Roast at 400 for 35-45 minutes or until tender enough for a fork to be inserted easily. Allow to cool. Remove the flesh from the skin, then pulse the flesh in a food processor until smooth. Strain in cheesecloth to remove excess liquid if necessary.

Whisk the pumpkin, brown sugar, eggs, half-and-half, ginger, cinnamon, allspice, cloves, and nutmeg in a bowl. Pour into the prepared crust; bake at 350 until the edges are set but the center still quivers, about 1 hour.