Step 1: Preheat your oven to 350°F (175°C) and line an 8×8 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
Step 2: In a medium bowl, combine the flour and sugar. Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse meal. Press firmly into the prepared pan.
Step 3: Bake the crust for 15-18 minutes until lightly golden. Remove from the oven and set aside to cool slightly while you prepare the filling.
Step 4: In a large bowl, whisk together the mashed sweet potatoes, maple syrup, eggs, heavy cream, cinnamon, ginger, nutmeg, and salt until completely smooth.
Step 5: Pour the sweet potato mixture over the par-baked crust and smooth the top with a spatula.
Step 6: Bake for 30-35 minutes, or until the filling is set around the edges but still slightly wobbly in the center.
Step 7: Allow the bars to cool completely in the pan at room temperature, then refrigerate for at least 2 hours before slicing into squares.