To the large bowl with the egg yolks, add sugar, olive oil, and lemon zest. Use an electric mixer to beat on medium-high speed for 1-2 minutes, batter should be well-combined.
Transfer pan to center rack of 325F (160C) oven. Bake for 55-65 minutes, or until a wooden skewer inserted in the center comes out clean or with a few moist crumbs.