Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving an overhang on two sides.

Place the dates in a heatproof bowl and cover with very hot water. Let soak for 10-15 minutes, then drain thoroughly.

Stir together the oat flour, rolled oats, cinnamon, and salt. Add the melted coconut oil, maple syrup, and vanilla. Mix until evenly moistened; the mixture should hold together when pressed.

Press the mixture firmly and evenly into the prepared pan. Bake for 12-15 minutes, until the edges are lightly golden. Set aside while you finish the filling.

Add the drained dates, ¼ cup hot water, maple syrup, almond butter, coconut oil, vanilla, cinnamon, and salt to a food processor. Process until as smooth as possible, stopping to scrape down the sides. The mixture should be thick and spreadable. If necessary, add more water 1 teaspoon at a time, using only enough to help it blend.

Fold the chopped pecans into the date mixture.

Spread the filling over the warm crust and gently press it into an even layer. Bake for another 18-20 minutes, until the pecans are fragrant and the edges of the filling look slightly darker. The center will still feel soft.

Cool completely in the pan, about 1 hour, then refrigerate for at least 2 hours.

Lift the chilled bars out using the parchment paper and cut into 16 squares. Serve chilled for the firmest texture, or let sit briefly at room temperature for a softer filling.