Make the rosemary syrup —On medium high heat, simmer the water, sugar, honey, & rosemary for 5 minutes before adding the blood oranges.Simmer for an additional 5 minutes.
Make the cake —Add the dry ingredients to a bowl. In a separate bowl, add the zest & juice of the oranges & buttermilk.After creaming the butter & sugar, add the vanilla, eggs, and rosemary. Mix until fluffy.
After creaming the butter & sugar, add the vanilla, eggs, and rosemary. Mix until fluffy.Alternate adding the dry ingredients & the orange juice & buttermilk mixture to the creamed butter & eggs while mixing.