Preheat oven to 350 degrees. Oil a jellyroll baking pan and line it with waxed paper oiled on both sides. Separate the yolks and whites in 2 bowls. Sift the flour and baking powder together.
Beat the yolks until light and lemon colored, about 20 minutes. The consistency should be very thick, and when you lift the beaters, the mixture should fall in one solid mass, known as the "ribbon stage". Add 1/2 cup of the sugar, 2 tablespoons at a time. Add the vanilla and beat 3 minutes more.
Whip the egg whites until soft peaks form. Add the remaining 1/2 cup sugar slowly until it makes a meringue. Add the whites to the yolks one-third at a time and fold in with a rubber spatula. Add the flour all at once and fold in.
Spread the batter in the pan and bake for 20 to 30 minutes or until the cake comes away from the sides of the pan. Let it rest for 5 minutes, then remove it from the pan and place on a clean tea towel that has been dusted with confectioners' sugar. Remove the waxed paper by rubbing the top of the paper with a dry cloth all over the surface and peeling off. Cover the cake with another tea towel and roll up the cake lengthwise in the towels, like a jellyroll, while still warm.
For the filling: Whip the cream and vanilla until soft peaks form. Add the confectioners' sugar. Add the fruit to the whipped cream and fold in.
For the soaking liquid: Mix the milks with a whisk. Add the liquor.
For the frosting: In a mixing bowl, beat the butter until soft and fluffy, about 10 minutes. Add the vanilla and mix for 2 minutes. Slowly add the confectioners' sugar until it is well incorporated. Add the milk.
To assemble the cake: Unroll the cake and remove the tea towel from the top layer. Spread the whipped cream mixture on the cake and, using the bottom as leverage, roll it up lengthwise. Transfer the cake to a serving tray seam side down. Make holes in the cake with a skewer and drizzle the soaking liquid, slowly, letting it absorb bit by bit. Cover the cake with the frosting.