How to Make It
Preheat the oven to 325°. Butter a 9-inch springform pan. Sift together the flour, polenta, baking soda and salt. In a small bowl, combine the olive oil, lemon juice and vanilla.
In a large bowl, beat the eggs with the granulated sugar at medium speed until thick, about 3 minutes. Gradually beat in the oil mixture and the lemon zest. Gently fold in the dry ingredients just until blended.
Scrape the batter into the prepared pan and bake for about 50 minutes, or until the center springs back when lightly pressed. Let the cake cool on a wire rack for 5 minutes. Remove the side and let cool completely.
In a medium bowl, whip the heavy cream to soft peaks. Transfer the cake to a serving plate and sift the confectioners' sugar over the top. Serve with the whipped cream.