- 3 oranges, divided
- 3 cups all-purpose flour
- 2 teaspoons baking powder
- 3/4 teaspoon ground allspice, divided
- Pinch of salt
- 1/2 cup butter, at room temperature
- 1 1/4 cups sugar
- 3 eggs, at room temperature
- 1 cup buttermilk
- 1/2 cup neutral-flavored oil
- 1 teaspoon vanilla extract
- 4 ounces 65% dark chocolate chips (available in bulk)
- 1/2 cup heavy cream
- Gray sea salt, for sprinkling
Preheat oven to 350° F. Grease and flour a 9- or 10-inch tube pan. Zest and juice 1 or 2 oranges; set aside 3 tablespoons zest and 1/4 cup juice for the recipe. Save remaining zest and juice for another use.
Sift together flour, baking powder, 1/2 teaspoon allspice and salt; set aside. In a separate bowl, cream together butter and sugar until light; beat in reserved orange zest. Beat in eggs, one at a time, until well combined.
In a large measuring cup, combine buttermilk, oil, reserved orange juice and vanilla. Add flour mixture in three parts alternately with buttermilk mixture and butter mixture, beginning and ending with flour. Beat until just combined — do not over mix.
Pour batter into prepared pan and bake until a toothpick inserted into the center comes out clean, 45 to 55 minutes. Cool cake completely in the pan and turn out onto a rack.
Place chocolate in a heat-proof bowl. Bring cream just to a simmer, and then pour over chocolate. Cover and let sit for 5 minutes. Add remaining allspice and stir until smooth. Pour warm ganache over cooled cake. Sprinkle cake with gray sea salt. Slice remaining oranges and use to garnish cake.