• Preheat your oven to 400°.
• Cut the cold butter into small pieces and place in a medium size bowl with flour, sugar and salt. Use your hand to mix the ingredients together, working the butter into the mixture using your fingers so that it has a course texture, it will be lumpy.
• Take out 1 1/2 cups of the mixture and set it aside to use as the topping.
• In a small bowl combine 1/4 cup flour, with baking soda, and zest add that to the remaining mixture in the bowl and mix by hand.
• In a small bowl whisk the egg, buttermilk and vanilla. Make sure that both the egg and the buttermilk are at room temperature. Once combined, fold in 1 cup of fruit and then add to the dry mixture and mix until just incorporated. Do not over mix.t