Total time: 2 hours 30 minutes
for the spice cake:
1 cup unsalted butter, cubed at room temperature
1 cup brown sugar
1 cup granulated sugar
zest of one orange
4 large eggs
1 teaspoon vanilla extract
3 cups all-purpose flour
2 1/2 teaspoons baking soda
2 teaspoons ground cinnamon
1/2 teaspoon ground ginger
1 teaspoon kosher salt
1/2 cup vegetable oil
juice of 1 orange
for the cinnamon orange frosting:
2 cups unsalted butter, room temperature
5 to 5 1/2 cups powdered sugar
zest of 1/2 an orange
1/4 teaspoon ground cinnamon
sprinkles, for decorating (optional)
Bench scraper (for scraping frosting)
1. Preheat your oven to 350°F. In the bowl of your mixer, beat together your butter, brown sugar, granulated sugar, and orange zest until light and fluffy, about 3 minutes. Scrape down the bowl, and add in your eggs, one at a time, until fully incorporated, scraping down the sides of the bowl as needed.
2. Whisk together your flour, baking soda, cinnamon, ginger and salt. Gradually add the flour mixture to the batter, scraping down the sides of the bowl as needed. Add in the vegetable oil and orange juice, and mix to combine.
3. Line 3 8-inch cake pans with parchment paper, and grease with butter or non-stick spray. Divide the batter evenly among the three pans (it will be a little thick. That's fine) and bake for 20-25 minutes, until set and lightly golden. Allow the cakes to cool completely before frosting.
4. To make the frosting, beat together your butter, powdered sugar, orange zest, and cinnamon. When you're ready, place a small dollop of frosting on a cake board or whatever surface you'll be frosting your cake on, then place your first layer on top of that dollop (this secures your cake in place). Use a serrated knife to level off the first layer so that the surface is level, then spread about 1/3 of your frosting over the surface of the first layer. Add the next layer, and again, level off the top so that it is even, and spread another ⅓ of your frosting over that layer. Add your final layer, level off the top, and use about ¼ of your remaining frosting to create a light crumb coat over your whole cake. The cake will not be fully frosted at this point - put it in the fridge for 15 minutes or so to firm up.
5. When ready, take the cake out again, frost with the remaining frosting, and use a bench scraper to go around your cake, deliberately scraping off frosting so that the sides of the cake show through, making your cake look "naked." Top the top of the cake with a little extra frosting and sprinkles if desired. This cake will keep well, covered and refrigerated, for up to 3 days.