Pre-heat oven to 350 degrees.
To make crust: Line an 8"-x-8" baking pan with parchment paper. In a food processor, pulse graham crackers, sugar, and salt until fine crumbs. Add melted butter and pulse until texture resembles wet sand. Press into pan and bake until golden for about 10 minutes.
Let cool completely. (I usually place my crust in the refrigerator until the filling is ready)
For the filling, add sweet potato, vanilla, cinnamon, all spice, melted white chocolate, and Greek yogurt to blender and combine until texture is smooth. Pour on top of graham cracker crust and spread evenly. Sprinkle pecans on top.
Place in refrigerator for about 2-3 hours or until set. You can let even let them set overnight in the refrigerator.
When bars are firm, cut into bars and serve!