Kittencal's Muffin Shop Jumbo Blueberry or Strawberry Muffins

Set oven to 375 degrees F.
Set oven rack to second-bottom position.
Generously grease 12 jumbo muffin tins, then cut out circles of parchment paper (or waxed paper) to fit into the bottom of each muffin tin.
In a large mixing bowl using an electric mixer blend the flour with sugar, butter and salt until mixture resembles a fine meal (reserve 1/2 cup of the mixture and transfer to a small bowl; set aside to sprinkle on top of muffins).
In a small bowl mix together baking powder, baking soda, cinnamon and lemon zest to the remaining flour mixture; mix until combined.
In a bowl whisk together buttermilk with eggs and vanilla to blend; add to the creamed mixture; gently mix just until combined (do not over mix!).
Carefully fold in the blueberries or chopped strawberries.
Divide the mixture between the muffin tins.
Sprinkle the reserved streusel over tops of muffins.
Bake for about 25-30 minutes, or until muffins test done (if using frozen berries baking time will increase slightly).
Cool for about 5 minutes in tins then carefully lift out to a rack.