Preheat oven to 350°F
With a non-stick cooking spray, spray two 9-inch round cake pans. Mix flour, baking powder, salt and baking soda. Set aside.
Beat butter and sugar in a large bowl with electric mixer on high until mixture is fluffy. Beat in flour mixture, milk, vanilla, eggs and oil on medium speed until blended.
Pour into pans and bake for 25-30 minutes or until toothpick comes out clean.
Cool for 10 minutes. Turn out on wire racks to cool completely.
To make frosting, cream butter and raspberry jam on low speed in a large mixing bowl.
Add powdered sugar and water to creamed butter. Blend on low for one minute, then scrape bowl. Continue to blend on high for two minutes until completely mixed.
Cut each cake round horizontally to make two layers each. Place one layer cut side up on cake plate and spread 1/2 cup of raspberry jam on top.
Add another layer cut side down with 1/2 cup raspberry frosting. Repeat with third layer.
Place last layer on top and frost sides and top of cake.
Pipe remaining frosting on top of cake. Garnish with fresh raspberries.