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)
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!