1. Preheat oven to 325°F and line a 9×13 inch pan with parchment paper, leaving an overhang.

2. In a bowl whisk flour, ginger, cinnamon, nutmeg, cloves, baking soda, and salt.

3. Cream butter and brown sugar until light, then beat in molasses and egg yolk until smooth.

4. Gradually stir in dry ingredients to form a dough, press into pan and bake for 8 minutes.

5. Beat cream cheese until smooth, add sugars then eggs one at a time, then sour cream, vanilla, molasses, cinnamon, and ginger.

6. Pour cheesecake mixture over crust and bake 35 to 40 minutes until center is set but slightly wobbly.

7. Let cool in oven with door ajar for 15 minutes, then chill in refrigerator at least 3 hours.

8. Lift from pan, slice into 16 bars, dust with powdered sugar or garnish as desired.

9. Store in airtight container in refrigerator up to five days or freeze up to two months.