Preheat the oven to 325 degrees F.
Lightly grease and flour a 10-inch tube pan using 1 tablespoon of the butter and 1 tablespoon of the flour, knocking to remove any excess. Set aside.
In a large bowl, cream the remaining 2 sticks of butter and sugar with an electric mixer on high speed until light and fluffy, scraping down the sides as needed, about 3 minutes. Add the egg yolks 1 at a time, beating well after the addition of each. Mix in the orange zest.
In a large bowl, sift the remaining 2 1/2 cups of flour, the baking powder, cinnamon, cloves, and anise. Mix into the egg mixture.
In a large clean bowl, beat the egg whites with clean beaters on high speed until stiff peaks form, about 5 minutes.
Using a rubber spatula, gently fold the egg whites into this batter. Pour the batter into the prepared pan and bake until golden and springy to the touch, 45 to 50 minutes.
Remove from the oven and let cool in the pan for 10 minutes. Turn out onto a decorative platter or cake plate and let cool.
In a medium saucepan, bring the Port to a boil and cook until reduced by 1/2. Remove from the heat and let cool slightly, then drizzle over the top of the cake. Garnish the cake with the orange segments and garnish the cake platter with the orange blossoms before serving.
Yield: 1 (10-inch) cake