Preheat oven to 350 F. Use 10-cup bundt pan.
In a medium bowl, mix 2 ½ cups flour, baking powder and salt and combine thoroughly.
In a separate large bowl, add together the softened butter, sugar and lemon zest and mix, using mixer, on high setting for about 5 minutes until even consistency is reached and the mixture reaches lighter color.
Add eggs, vanilla to the butter-sugar mixture and continue beating until well-incorporated.
Now we’ll be adding flour mixture into the butter-sugar mixture in 3 gradual steps, instead of dumping all of flour at one time. If you dump all of flour mixture into your butter mixture at one time, it will be more difficult to stir and you won’t get a smooth texture. So, we’ll be adding flour and Greek yogurt (or buttermilk) in 3 additions:
With your mixer on low speed, add ⅓ of flour mixture to butter-sugar mixture, beating just a little until all is well combined. Then follow by ¼ cup of Greek yogurt (or buttermilk). Add second ⅓ cup of flour mixture, beating with mixer just to combine. Follow by ¼ cup of Greek yogurt (or buttermilk), beating just to combine. Finally, add third ⅓ cup of flour mixture, followed by final ¼ cup of Greek yogurt (or buttermilk). Again, beat just enough to combine.
Make sure to have your mixer on low speed while adding flour, otherwise flour might fly around your kitchen. Make sure to not overmix or overbeat, use mixer just to combine the ingredients.
In a separate bowl, combine berries with 2 tablespoon of flour. This is supposed to prevent berries from clumping together and sinking.
Note about using frozen berries: I did make this cake with frozen berries without defrosting them. It's important that, if using frozen berries, they should not be clumped together, each berry should be separate (I freeze fresh berries by lining them on a cookie sheet). So you can use both fresh and frozen berries, and in either case you toss them with flour before adding to the batter.
Using spatula, fold berries into the cake batter, trying not to squish the berries.
Use 10 cup bundt pan. Spray your cake pan with a Baking Spray with Flour (which works great for bundt pans). Pour batter gently into prepared pan.
Bake for at least 60 minutes (depending on the oven, it could be as long as 1 hour 15 minutes), until the toothpick inserted into the center comes out clean. Mid-time through the baking, turn the pan around in the oven for even baking.
Remove the pan from oven, let it cool for 40 minutes on wire rack.