For the Almond Cake:
Preheat oven to 350°F (175°C). Grease the bottom and sides of two 9-inch round cake pans, line with parchment paper, and set aside.
In a large bowl, sift together the cake flour, baking powder, baking soda, and salt. Set aside.
In a stand mixer or using an electric mixer, beat the butter on medium-high speed until smooth, about 1 minute. Gradually add sugar, beating on high speed for 2 minutes once all sugar is incorporated.
Reduce speed to low and add egg whites in small batches, beating well after each addition. Scrape down the bowl as needed.
In a measuring cup, combine the vanilla extract, almond extract, milk, and sour cream. On low speed, alternate adding the flour mixture with the milk mixture, starting and ending with the flour.
Divide batter evenly between prepared pans, smooth tops, and bake for 25-30 minutes or until a toothpick inserted comes out clean.
Cool cakes in pans on wire racks for 15 minutes, then invert onto cooling racks to cool completely.
For the White Chocolate Amaretto Buttercream:
In a mixer, beat butter on medium speed until smooth. Gradually add confectioners’ sugar, beating on low until fully combined.
Add salt, cream, amaretto, and almond extract, mixing until smooth. Beat in melted white chocolate until well combined, then increase speed to medium-high and beat for 1 minute.
Assembly and Garnish:
Slice each cake layer in half horizontally, creating 4 layers. Place one layer on a cake stand, spread 1/2 cup frosting on top, followed by 1/4 cup raspberry preserves.
Repeat with remaining layers, ending with the last cake layer on top. Spread the remaining frosting over the top and sides of the cake.
Press sliced almonds around the sides of the cake and top with fresh raspberries.
Let the cake set for 20 minutes before serving. Store leftovers in the refrigerator for up to 2 days; bring to room temperature before serving.