For the crust: process pecans, the 4 un-soaked dates, ½ teaspoon salt, and 1 teaspoon vanilla until it presses together (add a little water if too crumbly). Press into a pie pan — no baking needed.
Chop yams/sweet potatoes and cook with a little water until just soft. Drain excess water.
Blend cooked sweet potatoes with the remaining salt, vanilla, soaked dates, coconut oil, lecithin, and pumpkin pie spice until smooth and thick, stopping to stir as needed.
Pour into the crust and chill overnight, or at least a few hours, before serving.
