Preheat oven to 350°.
Line a 9" round baking pan (with 2" sides) with a circle of parchment paper. Butter the pan, including the parchment, and evenly sprinkle with sugar and cranberries. Peel, core and thinly slice pears, pressing them lightly into bottom of the pan. Set aside.
Sift together flour, baking soda, cinnamon, cloves and salt. In a large separate bowl, whisk together sugar, olive oil, water and molasses, followed by egg and ginger. Gradually stir in flour mixture until just combined. Pour batter into the pan over pears. Bake for 50 minutes or until a toothpick comes out clean after inserting. Let the cake rest for 15 minutes. Run a knife around the outside edge. Place a cooling rack over the cake while still in the pan and carefully invert the pan. Cool cake on a rack. Serve warm. Garnish with whipped cream if desired.