Preheat oven to 325° F. Prepare 2 8-inch round cake pans by spraying with nonstick spray and lining the bottom with parchment paper.
In a medium bowl mix together the cake flour, baking powder and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar until homogenous. Add the oil and beat until the mixture lightens in color and texture. Add eggs, one at a time, mixing well after each addition.
In a separate bowl mix together the buttermilk, sour cream, lemon juice, vanilla, and lemon zest.
With the mixer on low speed, add half of the dry ingredients to the butter/sugar/egg mixture. Add the buttermilk mixture and then the rest of the dry ingredients. Stop mixing as soon as the dry ingredients are combined and the mixture is homogenous. Be careful not to overmix.
Toss the raspberry pieces in 1 tablespoon of all-purpose flour and then carefully fold into the lemon cake batter. Divide the batter evenly between the two cake pans and bake for 28-32 minutes, or until a toothpick inserted into the center of the cake comes out clean or with a couple cake crumbs on it.
Let the cake layers cool for 10-15 minutes and turn out onto a cooling rack to cool completely. If making in advance, wrap the layers in plastic and store in the freezer for up to two weeks.