Heat oven to 350 degrees F. Grease one 9x13 pan,or one bundt pan with butter.
Using an electric mixer, beat the oil and ¾ cup of the sugar together, then add the egg yolks and beat until thick and fluffy,scraping down the sides of the mixing bowl as necessary, 5 to 7 minutes. Meanwhile, combine the flour,baking powder, and salt in a bowl and set aside.
Mix in the dry ingredients until smooth. Add the lemon juice and zest and stir until blended. In a separate bowl, beat the egg whites until they foam, sprinkle in the remaining sugar while beating until the whites hold soft peaks; fold them in thoroughly, but as gently as possible. (the base batter in very thick)
Turn into the prepared pan and bake until a toothpick inserted into the center comes out clean, about 35 minutes. Let the cake cool in the pan for 15 minutes before removing it from the pan. Let cool completely before serving.
Heat the milk,cream and sugar in a small sauce pan until just boiling. Whisk lemoncello and cornstarch in a small bowl and add to cream and continue whisking until thickens slightly. Remove from the heat.
Ladle a small “puddle” of Lemoncello Cream on a dessert plate. Add slice of cake on top and dust with icing sugar. Optional---add a few berries and a sprig of Mint . Enjoy!