Preheat oven to 180 C / Gas 4. Spray a 38x25cm or similar sized Swiss roll tin with oil spray.
In a small bowl, mix together the cinnamon, nutmeg, ginger and allspice (or cloves). Set aside
In a large mixing bowl, on low speed, combine sponge cake mix, 1 egg, butter and 1/2 of the spice mix until crumbly. Press onto bottom of prepared tin.
In another large mixing bowl, beat cream cheese until fluffy. Gradually beat in sweetened condensed milk, the remaining two eggs, pumpkin, remaining spice mix and salt; mix well. Pour over base; sprinkle with pecans.
Bake 30 to 35 minutes or until set.
Cool, then chill in refrigerator. Cut into squares. Store covered in refrigerator.