Preheat oven to 325°F. Sift the flour, baking powder and salt together. Cream the butter and add the flour mixture gradually. Mix thoroughly. Beat the egg yolks until light; beat in the sugar gradually and add in the lemon juice. Combine with the butter-flour mixture and beat thoroughly. Fold in the beaten egg whites. Pour into well-greased loaf pan. Bake for 40 to 50 minutes.

Sauce: While cake is baking, combine berries, sugar, and water in saucepan. Heat to a boil. Let boil 1 to 2 minutes, stirring constantly. Reduce to simmer. Stir until desired consistency. Pour over or around cooled cake.

Fresh Whipped Cream: Pre-chill both the mixing bowl and mixing beaters. Pour the cream into the chilled bowl. Add the sugar. Beat with a mixer until smooth and thick. Start out rather slowly and increased speed as cream thickens. Do not beat too long or you will churn it into butter. Fold in vanilla. Top each slice of cake with fresh whipped cream. Note: Whipped cream should stand up for about 2 hours after whipping. After 2 hours, it will start to water and separate.