In a small bowl, combine the flour, baking powder, salt, remaining 1 teaspoon cinnamon and ginger. In a large bowl, with a mixer set on high speed, beat the remaining 12 tablespoons butter and the granulated sugar until fluffy. Reduce the speed to low; beat in the eggs and vanilla until well blended. Add the flour mixture alternately with the milk, beginning and ending with the flour. Beat just until blended.
Coat the skillet with vegetable spray or butter. Place the parchment paper in the skillet and arrange the pears in overlapping circles. Pour the remaining pear juice mixture over the pears and scatter the cranberries. Carefully spoon the batter over the fruit. Using a rubber spatula, spread the mixture evenly. Bake the cake until golden brown and a toothpick inserted in the center comes out clean, 45 to 55 minutes. Remove the cake from the oven and allow to cool for 10 minutes. Run a thin knife around the edges to loosen from the sides of the skillet. Invert the cake onto a serving plate. Remove the parchment paper. Serve the cake by itself or with ice cream, whipped cream, or crème fraîche.
Recommended variations: Apples and cinnamon: Substitute 3 peeled apples for the pears. When sautéing the apples in the skillet, add 1 additional tsp. of cinnamon.
Pumpkin and maple syrup: Peel and seed a small pumpkin and cut into 1/4-inch-thick slices 3 to 4 inches long. Substitute maple syrup for the brown sugar and sauté the pumpkin meat and 1/4 of the seeds 6 to 8 minutes, until fork-tender.