Moist chocolate cake topped with a tangy bright HIbiscus reduction.
Replace the whisk with the paddle attachment. With the mixture on medium-low speed add butter one slice at a time until all of the butter has been incorporated. The mixture should be silky smooth and thick. The mixture may begin to look curdled, keep mixing until it is smooth. This can take 10 minutes or so. Mix in salt and vanilla. Add hibiscus reduction and keep mixing until the mixture is silky again.
Chocolate Zucchini Cake batter can be baked in a 9 x 13-pan, 12 x 17-inch sheet pan, two 9-inch round cake pans as well.
This little step will help you create extremely moist cakes every time. While the cakes are still hot (YES! still hot) wrap each one in plastic wrap and place in the freezer. I like to make my cakes ahead of time, so this tip works. They will keep in the freezer for quite a while. If storing for more than a few days, wrap in plastic THEN wrap in foil. The cakes will keep for weeks.
If you want to use the cakes the same day, wrap in plastic wrap and cool in the refrigerator for a few hours. Make sure the cakes are completely cold before icing.
Buttercream can be made in advance and stored in the refrigerator for 3-4 days or frozen for several weeks. Thaw frozen buttercream overnight in the refrigerator. Bring to room temperature then beat until creamy.
If the buttercream happens to have a curdled look to it, that means it is too cold. Take a warm washcloth and place it on the bottom of the mixing bowl while beating. Continue this process just until the mixture is silky smooth. Not melt the butter!