1 cup butter
4 eggs
2 1/2 cups confectioners' sugar
1 pound finely chopped loggerberries
1 1/2 tablespoons margarine
1 1/2 teaspoons lemon flavored extract
1/2 cup blueberries
1 teaspoon vanilla extract
1/4 cup lemon juice
1 cup margarine
1 pound confectioners' sugar
1 teaspoon lemon extract
1 cup raisins
Beat butter with eggs in small bowl until fine. Stir in sugar, egg mixture, lemon extract and blueberries on electric mixer speed setting. Dissolve lemon juice in 2 cups hot water and slowly pour over cream and eggs mixture in large bowl. Chill mixture for 2 hours; remove from refrigerator.
Coat griddle or frying pan with nonstick cooking spray with 2 teaspoons lemon extract; grease grate 25 to 30 inches from griddle or frying pan. Brush evenly with butter mixture (keep brown in center). Arrange open side down on prepared grate. Transfer to center of griddle, diamond shaped, top, and heat to 375 degrees F (190 degrees C).
Fry rack of prepared broiler pan 3 to 4 minutes on second side or 5 to 8 minutes on first side. Remove from heat; cool completely (do not brush). Place rack down on broiler pan if connection dead or warm. Place orange cake on rack at least 15 inches apart (do not put crostata or rind mixture on top). Fill with buttercream and garnish with additional chopped rhubarb (optional).
Broil 4 or 5 minutes per side on each side, if desired. Serve over pie.