How to Make It
Preheat the oven to 275°. Spray a 6-inch springform pan with vegetable oil spray. Wrap the outside of the pan tightly with foil and set it in a small roasting pan.
In a medium bowl, using an electric mixer, beat the cream cheese and sugar at medium speed until smooth. Add the quark and beat just until blended. Add the egg and egg yolks, one at a time, beating well between additions. Beat in the Cointreau. Pour the mixture into the prepared pan.
Add enough hot water to the roasting pan to reach halfway up the side of the springform pan. Bake for about 1 hour and 15 minutes, until the cheesecake is slightly jiggly in the center and set around the edge. Remove it from the water bath and run a knife around the edge of the cake to allow it to settle in the pan as it cools. Cover and refrigerate overnight.
Preheat the oven to 350°. Butter and flour a 6-inch cake pan. In a small bowl, whisk the flour with the baking powder, ground spices and salt. In a medium bowl, using an electric mixer, beat the brown sugar with the egg and egg yolk at medium-high speed until light and fluffy. In a microwave-safe bowl, melt the butter in the milk. Stir in the molasses, fresh ginger and vanilla. In 3 alternating additions, beat the dry and wet ingredients into the egg mixture.
Scrape the batter into the prepared pan and bake in the lower third of the oven for 35 to 40 minutes, until springy. Let the cake cool in the pan for 20 minutes, then turn the cake out onto a rack. Turn it right side up and let cool completely.
Using a serrated knife, carefully slice the rounded top off of the gingerbread cake to make it level. Invert the cake (cut side down) onto the cheesecake. Place a plate over the cake pan. Holding both the plate and pan, invert the entire cake onto the plate. Remove the ring, then carefully lift off the pan bottom. Garnish with the candied kumquat slices and serve chilled.