This is a very light cake, similar to a lemon drizzle but with a ton more flavor. The rosemary and orange add delicious floral notes. A fluted Bundt pan looks especially nice. Prepare the crystallized rosemary sprigs at least 6 to 8 hours (or the day before) before serving the cake, which will keep in a sealed container at room temperature for up to three days.

FOR THE CRYSTALLIZED ROSEMARY:

• 10 small rosemary sprigs, no more than 1 inch/3 centimeters each in size (see note)
• 1 egg white, lightly whisked
• 2 teaspoons granulated or superfine sugar (caster sugar)

FOR THE CAKE:

•  About 2 tablespoons/30 grams unsalted butter, softened, for greasing the pan
• 2 cups/240 grams all-purpose flour (plain flour), more to flour the pan
• ¾ cup/160 milliliters extra-virgin olive oil
• ½ cup plus 1 teaspoon/120 grams superfine sugar (caster sugar)
• 1 tablespoon finely grated orange zest (from about 1 1/2 oranges)
• 1 ½ tablespoons/7 grams packed finely chopped rosemary leaves
• 2 large eggs
• ½ cup/130 grams sour cream
• 2 teaspoons baking powder
• ¼ teaspoon salt

FOR THE ORANGE ICING:

• 1 ½ tablespoons freshly squeezed orange juice
• 2 ½ teaspoons freshly squeezed lemon juice
• 1 ¾ cups/175 grams sifted confectioners’ sugar, or 1 1/2 cups/150 grams sifted icing sugar