In the bowl of an electric mixer, add the brown sugar, honey and cooled browned spice butter. Using a whisk attachment, whip until the mixture is combined and sugar is almost dissolved on high speed for about 3 – 4 minutes.
Add one egg at a time, beating the mixture well. Add in the vanilla, mixing for another 30 seconds. Turn the speed to low, add the flour mixture and sour cream porter liquid. Mix until just combined, leaving no lumps or wet patches. Divide the cake batter evenly into the prepared cake pans.
Place into the center of the oven and cook for 25 – 30 minutes, or until a probe thermometer reads 200°F/93°C. Remove from the oven, let rest for 15 minutes. Then using a knife, trace the edge of the inside cake pan, to loosen it. Invert the cake onto a wire rack and let cool completely. This cake can be made 4 hours to 3 days ahead. Once fully cooled, wrap in plastic wrap.