Makes one 23cm cake or two sponge cakes

Ingredients:

1 small grapefruit (325gm)
2½ cups sugar
3 cups (375 g) all-purpose flour
2 tsp. baking powder
1 tsp. baking soda
1 tsp. salt
2–3 Tbsp. chopped fresh rosemary (dependent on the herb potency you want)
4 eggs
6 Tbsp. Juno Rosemary infused olive oil
Icing sugar to decorate

Method:

1. Preheat oven to 350° F. Grease and flour a 23cm round cake tin and set aside.
2. Slice a small amount off the bottom and top of the grapefruit to reveal the flesh. In a small pot, cover the grapefruit with water and bring to the boil. Cook for about 1 minute and drain off the water. Repeat the boiling, cooking, and draining twice more.
3. Put the blanched grapefruit, 1 cup sugar, and 3 cups water into the small pot and cook over a medium heat for about 20 to 30 minutes. Stir frequently until sugar is dissolved and the grapefruit rind is tender. 
4. Remove the grapefruit from the liquid to cool and save the liquid for later to finish off the cake.
5. In a bowl, sift the flour, baking powder, baking soda, salt, then add the chopped rosemary. Set aside.
6. When grapefruit is cool, cut in half and scoop the flesh into a food processor. Scrape the white pith from the rind and discard. 
7. Add the grapefruit rind into the food processor. Add the eggs and pulse until the grapefruit is a chunky purée.
8. Add the remaining 1½ cups sugar and the Rosemary infused olive oil to the food processor. Blend to combine. Add the dry ingredients in two batches briefly pulsing to bind. Do not over mix.
9. Pour the mixture into the prepared baking tin.
10. Bake 40 to 50 minutes, until a toothpick inserted in the center of the cake comes out clean and the edges and top are just turning golden brown. Remove from oven and place tin on a wire rack.
11. Brush a small amount of the reserved grapefruit cooking liquid on top of the cake. Let cool for about 10 to 15 minutes before removing from the pan to cool completely.
12. Sift a generous amount of icing sugar over the top and serve with mascarpone cream.