Preheat oven to 350°. Spray 3 (9-inch) round tall-sided cake pans with baking spray with flour. Line bottoms with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition. Beat in raspberries and vanilla.
In a medium bowl, whisk together flour, baking powder, and salt. In a small bowl, combine buttermilk and food coloring. Gradually add flour mixture to butter mixture alternately with buttermilk, beginning and ending with flour mixture, beating until combined after each addition. Divide batter among prepared pans, smoothing tops with an offset spatula.
Bake until a wooden pick inserted in center comes out clean, 35 to 40 minutes. Let cool in pans on a wire rack for 10 minutes. Remove from pans, and let cool completely on wire racks.
Spread Raspberry Frosting between layers and on top and sides of cake. Garnish with raspberries and flowers, if desired.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/raspberry-cloud-cake-recipe/