Preheat the oven to 350℉. Butter and flour a 9-inch springform pan or cake pan.
Add the olive oil to a small sauté pan. Add the fresh rosemary. Bring the pan to a medium-low temperature for 10-12 minutes. For an electric stove, this is a “3” on a scale of “1-10”. It should just start to bubble at that time. Remove the rosemary sprigs and allow the olive oil to cool to room temperature. You now have rosemary infused olive oil. You can place the sauté pan in the fridge on a potholder to speed up the cooling process.
In a large mixing bowl, combine the now cool extra virgin olive oil, whole milk, eggs, lemon zest, lemon juice, and vanilla extract.
Add the granulated sugar and stir to combine. Add the baking powder and salt and combine.
Add the flour and combine.
Bake for 26-28 minutes or until the top has a domed shape, it is lightly brown and a toothpick inserted in the middle comes out clean.
Notes
Olive Oil: Use Extra Virgin Olive Oil, choose either one you already like or Spanish olive oil from Trader Joe's or Costco.Mix By Hand: This is a simple cake and can be mixed by hand in one bowl with a large mixing spoon.Don’t Overmix: Don’t overmix the batter. The more you mix the more gluten is developed which results in a tougher cake.Prepared Baking Dish: Butter and flour the baking dish to make it easy to cut and remove clean slices.Toothpick Test: Insert a toothpick into the center of the cake on the earlier side of the allotted baking time to check for doneness. The toothpick should come out clean without any wet batter or moist crumbs. This will help to ensure that the cake is fully cooked, which will prevent it from sinking afterward.