If using dry milk powder, wipe out now-empty sauté pan then sprinkle in dry milk powder. Cook over medium-low heat, stir occasionally, until powder starts to toast. Once it starts to toast, start stirring constantly to evenly toast. Continue cooking until deeply golden brown, about 7 minutes. Remove from heat and transfer powder to a food processor.
Add pumpkin, brown sugar, ginger, cinnamon, nutmeg, cloves, salt and pepper to processor with powder and process 1 minute.
Transfer pumpkin mixture to now empty sauté pan over medium-high heat and bring to a sputtering simmer, cook, stirring constantly, until thick and shiny, about 5 minutes.
Whisk mayo and milk into pumpkin and cook just until it starts to bubble then remove from heat.
Process eggs in now-empty food processor until foamy, about 5 seconds. With processor running, gradually stream in warm pumpkin mixture.
Pour warm filling into warm pie shell. (Pour any excess filling into pie after 5 minutes of baking.) Bake pie until filling is puffed, dry-looking, and center slightly wiggles when gently shaken, about 25 minutes. Transfer pie to a wire rack and cool completely.