Preheat oven to 400. Mix dry ingredients in a large bowl. Using a pastry blender or two butter knives, cut in cold butter until mixture resembles coarse meal. Stir in berries & lemon zest. In a separate bowl, combine wet ingredients together, then pour wet mix in with the dry and use a rubber spatula to combine. Do not overmix!
Divide the dough in half (it will be sticky) and place each half on a lightly greased or parchment-lined baking sheet. Cut into large circles with a cookie cutter or large cup. Top with a sprinkle of sanding sugar, if desired.
Bake 14 - 18 minutes, or until edges are golden brown, and set aside to cool for about 10 minutes. Whisk glaze together in a small bowl until smooth and drizzle over the scones. Scones are best served warm.