Mix all ingredients in a saucepan, except crust and walnuts, until thoroughly combined and smooth. Cook over medium heat until very thick and bubbles pop out of pan (about 20 minutes, more or less); stir frequently.
Pour into half-baked piecrust, sprinkle with walnuts. Bake at 425 Degrees for 10 min., then reduce heat to 350 degrees for another 30 min. or until knife placed into pie comes out clean. When crust starts to brown, cover edge with strips of foil to prevent burning.
If using fresh pumpkin, always mix ingredients in a blender on the puree cycle until creamy before cooking.