Preheat oven to 180C/350F/Gas 4 and line a 9x13" baking dish with parchment paper.

To make the crust: Place flour, butter, and pecans in a mixing bowl and mix to combine. Press down on bottom of baking pan. Bake crust for 15 minutes and let cool completely.

Reduce the oven to 150C/300F/Gas 2.

To make vanilla layer: With an electric mixer, combine the cream cheese, sugar, and vanilla until smooth. Add eggs and mix at low speed until smooth and fluffy.

Spread half this mixture evenly onto cooled crust, and set other half aside.

To make the pumpkin layer: With an electric mixer, combine cream cheese, sugar, pumpkin, and pumpkin pie spice until smooth. Add egg and mix at low speed until smooth and fluffy.

Add the pumpkin layer to the pan, followed by the other half of the vanilla layer and use a knife to create a swirl effect.

Bake for 35-40 minutes or until set.

Remove cheesecake from oven and leave to cool for one hour before placing in the fridge for a minimum of 3 hours before cutting into bars.