Place the squash in a large saucepan, and fill it up with water so that that the water almost covers the squash. Bring the water up to a boil, then reduce to simmering. Boil the squash until it is tender and easily pierced with a fork. Set aside in the water to cool.
Place the dates in a small bowl with the baking soda, and cover with hot water. Allow to sit for about 5 minutes, until softened.
Remove the squash from the water, and mash it with a fork (Joanne says you can mash it skin and all, but I peeled mine). Reserve 1/2 cup of squash puree for the recipe, and the rest you can use for other purposes.
Heat the squash puree, the vanilla beans and the milk together, either in the microwave, or on top of the stove, until they all combine nicely together. In your blender, add the squash/vanilla/milk mixture, the oil, the eggs, and the drained dates. Zap it on puree until the mixture is frothy and all combined.
In a large bowl, combine the dry ingredients well. Add the wet to the dry, and mix.
Pour the batter into a parchment-lined cake tin (8" or 9" round or square), and bake in a 350 degree oven for about 35 to 40 minutes, or until the cake springs back when touched. Allow to cool, slice and serve.