1 tablespoon plus 1/2 cup unsalted butter, at room temperature
2 teaspoons plus 4 teaspoons finely minced fresh rosemary leaves
2 tablespoons plus 3/4 cup polenta or stone-ground corn meal
1 cup all-purpose flour
2 teaspoons baking powder
1 teaspoon salt
1/2 cup olive oil
5 large eggs, at room temperature (yes, this is a lot of eggs, but well worth it!)
2 large egg yolks (Make yourself an egg white sandwich with the leftover whites and feel virtuous!)
1/2 teaspoon almond extract or 1 teaspoon vanilla extract (I used almond extract - it felt fancy)
1 1/3 cups sugar (I ran out of white sugar after about a cup, and used brown for the rest. It seemed to work fine.)
1. Preheat the oven to 350°F.
2. Smear 1 tablespoon butter all over the inside of a 10-cup (2.5-liter) Bundt cake or tube pan. (I had neither, luckily Selena, who lives down the street, lent me her Bundt pan - maybe a regular cake pan would work too if the volume matched?). Sprinkle the 2 teaspoons of rosemary evenly into the pan, then dust with the 2 tablespoons (20 g) of polenta, tilting the pan to coat the sides.
3. To make the cake, in a small bowl, sift together the flour, 3/4 cup (130 g) polenta, baking powder, and salt. Set aside. In a separate bowl, whisk the olive oil, eggs, egg yolks, and almond or vanilla extract.
4. In a stand mixer fitted with the paddle attachment (or in a bowl by hand), beat together 1/2 cup (4 ounces/115 g) butter and the sugar on medium speed until light and fluffy, 3 to 5 minutes. With the mixer running, slowly dribble in the egg mixture, a little at a time, until completely incorporated. Stir in the flour mixture along with the 4 teaspoons of rosemary until just incorporated. Don't over mix.
5. Scrape the batter into the prepared cake pan and smooth the top. Bake until a toothpick inserted into the center comes out clean, about 40 minutes. Let cool for about 30 minutes, then invert the cake onto a serving plate. (Mine was done at exactly 40 minutes)