1. 1. Preheat your oven to 350°F. Grease and flour three 7-inch round cake pans.

2. 2. In a medium bowl, whisk together the cake flour, baking powder, and salt. Set aside.

3. 3. In a stand mixer, cream the butter, oil, and granulated sugar until light and fluffy.

4. 4. Add egg whites one at a time, mixing well after each addition. Stir in sour cream, vanilla extract, and almond extract.

5. 5. Alternate adding the dry ingredients and milk to the batter, mixing just until combined.

6. 6. Divide the batter among the prepared pans and bake for 25-30 minutes or until a toothpick comes out clean. Cool in pans for 10 minutes before transferring to a wire rack.

7. 7. For the raspberry filling, combine frozen raspberries, granulated sugar, and lemon juice in a saucepan over medium heat until juices are released.

8. 8. In a small bowl, whisk cornstarch and water to create a slurry. Add to raspberry mixture and stir until thickened. Cool completely.

9. 9. For the buttercream, set up a double boiler and whisk egg whites and powdered sugar until warm and sugar dissolves.

10. 10. Beat the mixture until stiff peaks form. Gradually add cubed butter until incorporated. Mix in vanilla and almond extracts.

11. 11. Assemble the cake by layering with raspberry filling between layers and frosting with buttercream.

12. 12. Garnish with fresh raspberries and slivered almonds.