Place the pitted, chopped dates into a blender with the non-dairy milk and vanilla, and set aside for at least 30 minutes so that the dates may soften.
Combine the flour and spices in a mixing bowl.
After soaking, blend the dates, non-dairy milk and vanilla until smooth (1 to 2 minutes). Pour this mixture, along with the pumpkin, into the bowl of flour and spices. Mix until smooth with an electric beater, tossing in the nuts last. (The batter will be thick.)
Scrape into an 8 by 8-inch baking pan lined with parchment paper (or use a silicone baking pan). Bake for 30 minutes at 375 degrees. Let cool 10 to 15 minutes before slicing the squares and serving. The longer they cool, the firmer they will become. Optional: add Nutty Frosting below just before serving.
Nutty Frosting
Place all ingredients into a blender jar and let sit for at least 30 minutes, so the nuts and dates can soften.
After soaking, blend all ingredients until smooth. Use immediately or chill for a couple hours or overnight to thicken.