Preheat oven to 325°F (163°C). Generously grease a 10-12 cup pan with butter or nonstick spray. (I used an 8" round pan, but a square or bundt pan will work really well here too, or use two 9" x 5" loaf pans).
Using a handheld or stand mixer fitted with a paddle or whisk attachment, beat 1.5 cups butter on high speed until smooth and creamy, about 2 minutes.
Scrape down the sides and bottom of the bowl with a rubber spatula. Add 1 cup room temperature cream cheese and beat on high speed until completely smooth and combined, about 1 minute.
Add 2 cups sugar and beat on high speed until combined, about 1 minute, then add 1/3 cup sour cream and 2 tsp vanilla essence and beat on high speed until combined and creamy. Scrape down the sides and bottom of the bowl with a rubber spatula.
Turn the mixer on low speed, add the 6 eggs in one at a time allowing each to fully mix in before adding the next. Careful not to overmix after the eggs have been added.
Once the 6th egg is combined, stop the mixer and add the cake flour, baking powder, and salt. Beat on medium speed *just* until combined. Do not overmix! Using a rubber spatula or sturdy whisk, give the batter a final turn to make sure there are no lumps at the bottom of the bowl. The batter will be a little thick and very creamy.
Pour/spoon batter evenly into prepared pan. Bang the pan on the counter once or twice to bring up any air bubbles. Bake for 80-95 minutes (if using two loaf pans it should take about 60 minutes). Loosely tent the baking cake with aluminum foil halfway through bake time to ensure the surface does not over-brown. The key to pound cake is a slow and low bake time. Trust the process!
Use a clean toothpick to test for doneness. Insert the toothpick in the centre of the cake. Once it comes out completely clean, the pound cake is done. This is a large heavy cake so don’t be surprised if it takes longer in your oven. If it needs longer, bake longer!
Remove cake from the oven and allow to cool for 2 hours inside the pan. Then invert the slightly cooled pound cake onto a wire rack or serving dish. Allow to cool completely.
Slice and serve with optional toppings like homemade whipped cream & fresh berries.
Cover leftover cake tightly and store at room temperature for up to 2 days or in the refrigerator for up to 5 days or in the freezer for upto 3 months. Allow to come to room temperature before serving.