To make the crust: Heat oven to 325°F. Line an 8-inch square cake pan with a sheet of aluminum foil that goes up the sides.
Mix together all the ingredients and press it into the prepared pan. Bake for about 10 minutes or until just toasty and golden brown.
To make the filling: In a stand mixer fitted with the paddle attachment (I really like the rubber edged attachment for this. Less scraping the bowl), mix the cream cheese on low speed until smooth. Add the sugar and mix until incorporated, scrape the bowl often. Add eggs one at a time, scraping bowl between them. Mix in sour cream.
Separate out 1/2 cup of the filling into a bowl and add pumpkin puree, spices and vanilla. Place the pumpkin cheesecake mixture into a pastry bag fitted with a round tip or a squeeze bottle.
Pour the remaining plain cheesecake over the baked crust and shimmy to settle it flat. Pipe the pumpkin cheesecake over the top of the plain in a zigzag pattern, then draw a toothpick through it in the opposite direction to create the swirly or marbled pattern.
Bake in a water bath (this will help keep the shape of the swirls) for about 30-35 minutes until the cheesecake is set, but still wobbles in the center. Cool completely on a wire rack, then chill in refrigerator until firm, at least 4 hours or overnight (I cheated and after they were room temperature, I put them in the freezer for 45 minutes and cut them.)
Use the overhanging foil to lift the bars out of the pan. To cut the cheesecake dip a sharp knife in hot water.