Preheat oven to 350. Grease two 9"x5" loaf pans. To bake pound cake: Cream together butter and sugar in large mixing bowl or stand mixer. Add in the eggs. Beat until incorporated. Add in the vanilla. Combine flour, baking soda, baking powder, and salt in a large mixing bowl. Alternately add flour mixture and buttermilk to egg mixture. Mix until just incorporated. DO NOT OVERBEAT. Pour half of the cake batter into each loaf pan. Bake for 55-60 minutes or until a toothpick inserted in the center comes out clean. Meanwhile, combine pudding mix and milk in a large mixing bowl or stand mixer. Beat until pudding it begins to thicken. Cover and place in refrigerator for at least 5-10 minutes to set. Add the whipping cream to a cold mixing bowl and beat until stiff peaks appear. When pound cake is cool, cut one loaf into bite-sized cubes. Place three-four cubes into the bottom of a mason jar, canning jar, or dessert glass. Top with a few raspberries, strawberries, and blueberries (each). Then spoon in pudding to cover berries. Then a layer of whipping cream. Repeat until jar or glass is full, making sure to top with whipped cream and a few berries. Keep in the refrigerator until ready to serve.