Preheat oven to 325 degrees F. Coat a 9-inch x 13-inch baking dish with non-stick cooking spray. Set aside.
In a medium bowl, combine flour and baking soda. Set aside.
In a large pot over medium-low heat, whisk together butter, corn syrup, honey, sugar, Guinness, ginger, cinnamon, and cloves. Cook until sugar has dissolved and butter is melted, stirring occasionally.
Remove pot from heat, and whisk in flour mixture. Keep whisking until everything is combined and smooth.
In a medium bowl (I used the same one the flour was in), mix together sour cream and eggs. Whisk sour cream mixture into the batter until smooth and incorporated.
Pour batter in prepared pan. Bake for 45 minutes. When the gingerbread is ready the top will be shiny and rise up and the sides will be pulling away from the pan.
Carefully remove from the oven and place on a wire rack to cool completely. Generously dust the gingerbread with powdered sugar and then cut into 12 squares. Serve immediately or store in an air-tight container.
If you have Golden Syrup available where you live - substitute 1 cup Golden Syrup in place of the corn syrup and honey.