In a food processor outfitted with an "S" blade place 3/4 cup of pecans, along with all of the sweet potatoes, water, dates, cinnamon, and vanilla. Puree to a smooth consistency. Pour the mixture into a glass casserole dish for serving.
In a small bowl, combine the remaining pecans, salt and agave or maple syrup and toss to coat. Scatter the pecan topping over the casserole. Serve
The casserole can be warmed in the dehydrator by placing it inside at 105° for 30 -- 45 minutes just before serving.