In a medium bowl, sift together the cake flour, baking powder, and salt. Set aside.

In a large bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth, about 1 minute. Add cream cheese and continue beating until smooth and combined, scraping down sides as needed. Add sugar and beat until light and fluffy, about a minute. Add the sour cream and vanilla, beating until smooth.

Adjust speed to low and gradually add the eggs one at a time, allowing to combine before adding the next egg. As soon as the last egg is added, turn off the mixer to avoid overbeating.

Add the flour mixture to the mixer and turn speed to low just until combined. Using a spatula, scrape down the bowl and stir by hand to be sure any pockets of flour are combined.

Spray a loaf pan with nonstick spray. Spoon the batter into the prepared pan. The batter will be quite thick and creamy. Smooth the top with a knife or spatula, then place directly into the cold oven. Turn the oven to 325°F and bake 70-75 minutes, or until golden and a toothpick comes out clean.

Cool cake in the pan for 10 minutes before inverting onto a rack to cool completely.

Dust with powdered sugar and serve with whipped cream and fresh berries or a berry sauce.

To make a simple berry sauce: combine 2 cups of berries/cherries, ½ cup granulated sugar, and ½ cup water in a medium saucepan over low heat for 10-15 minutes. In a separate bowl, combine ½ teaspoon corn starch and ½ teaspoon water and add to the saucepan, stirring to combine. Continue simmering until thickened and syrupy. Sauce will thicken more as it cools. Set aside to cool to room temperature while the cake is cooling.

Dust cooled cake with confectioners sugar and serve with berry sauce and whipped cream, if desired.