Puree tofu in blender (add water if necessary to achieve smooth consistency). Add the rest of the ingredients and blend until smooth. Pour into safe pie crust and bake at 450 °F for 15 minutes, then reduce oven temperature to 350 °F and bake for approximately 50 minutes.
Pie will be a bit jiggly when removed from oven (unlike an eggy pumpkin pie); let it cool for a bit, then refrigerate. It will firm up beautifully!
To avoid milk, substitute soy or coconut milk.
In place of pumpkin pie spice, you can use 1 tsp cinnamon, and any combination of nutmeg, cloves, allspice, and/or ginger equaling 1 tsp.