Lemon Custard Cake

Preheat oven to 350 degrees F.
In a large bowl, sift together flour, sugar, baking powder, baking soda and salt. Mix in oil and vanilla until a thick batter has formed.
Add milk. Start with 1/2 cup. If the batter still seems a little think, add another 1/4 cup. Make sure to whisk thoroughly so there are no clumps. Lastly, add in vinegar.
Pour cake batter into a prepare 8-inch cake pan. Bake for approximately 20 minutes or until cake is golden and the tester comes out clean. Remove from oven and let cool on a wire rack before transferring to a cake plate.
Using a serrated knife, carefully slice cake in half. If the center still feels warm, leave to cool completely for an extra 15 minutes or so.
Lemon Custard:
In a saucepan or double broiler, combine sugar, lemon juice and zest over medium-low heat or simmering water.
In a bowl, beat one egg and add to the lemon/sugar mixture. Stir constantly, until mixture has thickened (about 8 minutes). Alternate and take on/off heat while whisking. Remove custard from heat and stir in butter. Set aside to cool completely and then chill in the refrigerator for one hour.
In a medium bowl, whip 1 cup of heavy cream with a teaspoon of confectioners' sugar.
Spread the chilled Lemon Custard on one layer of the cake. Spoon a dollop of whipped cream in the center and place the other cake on top. Use the remaining whipped cream and spread over the cake entirely. Grate a chocolate candy for garnish (I grated a Ferrero Rocher).