Preheat oven to 375°F. Grease a 9x13 in baking pan with non-stick spray and set aside.
For the crust, in the bowl of a food processor, combine the gingersnaps, granulated sugar and flour. Pulse on high until crumbs form. Add the melted butter and mix again until the crust starts to stick and pull away from the edges. You can also crush them by hand and mix together with a wooden spoon. Press mixture into the bottom of the prepared baking pan and set aside.
In a large bowl, combine the pumpkin, brown sugar, salt and pumpkin pie spice. Stir in half and half and eggs just until combined, being careful not to overmix. Spread batter in crust-lined pan.
Bake 40-45 minutes in preheated oven or until a knife comes out clean. Sprinkle with pecans and cool completely in the pan on a wire rack. Cut into bars.
To store: cover bars and store in the refrigerator for up to 2 days, do not freeze.