Grease and flour the bottom and side of a 10-inch tube pan or a 10-inch fluted tube pan. Set aside.
In a medium bowl, stir together cake flour, baking powder, and salt. Set aside.
In a large bowl, beat butter, granulated sugar, and vanilla with an electric mixer on medium speed until well combined. Add the 3 eggs; beat until the mixture is light and fluffy.
With mixer at low speed, add flour mixture alternately with milk, beating after each addition. Fold in anise hyssop blossoms. Spoon the batter into the prepared pan.
Bake in a 350 degree F oven about 40 minutes or until a wooden toothpick inserted into the cake comes out clean.
Cool the cake on a wire rack for 10 minutes. Loosen side of cake from pan. Remove cake from pan and cool completely. Sift powdered sugar over cake. Makes 12 servings.