In a heat-safe bowl, pour the piping hot water over the dates, oats, and ground flaxseed; allow to soak for 10 minutes.
In a high-speed blender or food processor, combine the date-oat-flax mixture, maple syrup, ½ cup pecan halves, molasses, vanilla, and rum extract. Blend on high speed until smooth, 1-2 minutes. Taste the filling, adjust the vanilla, maple syrup, and add salt, if desired. Stir in 1 cup pecans.
Pour the pecan filling into the pie crust, leaving 1-2 tablespoons in the blender.
Pour the remaining half cup of pecans into the blender and stir to coat the pecans with remaining filling. Remove the coated pecans and place on top of the pie filling.
Place the pie on the center rack in the oven and bake for 45 minutes. You'll know the pie is ready when the center of the pie is soft and puffy but the edges look somewhat dry and have tiny air cracks in it.
Cool the pie at room temperature for at least two hours.
Store covered at room temperature for 3-4 days or up to 1 week in the refrigerator.** If refrigerated, take the pecan pie out at least 30 minutes before serving – the texture is best served at room temperature.
Serve plain or with non-dairy whipped topping.
Notes
* Use your favorite pie crust.** You can make this pie in advance and freeze this pie. Thaw fully for in the refrigerator.