Grease and flour 3 - 8" cake pans. Whisk together flour, baking powder, and salt.
Beat butter and sugar on medium speed 1-2 minutes. Add 1 cup raspberries. Blend 15 seconds. Add eggs one at a time (mixture will look curdled). Add vanilla on low. Beat in flour and buttermilk alternately - beginning and ending with flour. Add food coloring. Divide batter among 3 pans.
Bake until toothpick comes out clean - about 23-25 minutes. Cool in pans on wire racks 10 minutes, then invert on racks to cool.
Toss together jam and remaining 3 cups raspberries in a bowl. Place 1 layer cake on plate. Top with 1/2 jam mixture. Repeat 1 more time. Top with remaining cake layer. Frost top and sides and decorate with Raspberry Cream Frosting.