Set a rack in the upper third of the oven and preheat to 425 F. Line a baking sheet with parchment or a silpat for easier cleanup.
Stir together the flour, Clabber Girl Baking Powder, baking soda and salt. Mix in the butter using a pie cutter or your hands. There should be large, visible chunks of butter to assure a flaky texture. Stir in the cream using a wooden spoon, just until the dough pulls together. You may need a bit more cream if the dough seems stiff.
Knead the dough on a floured board just a few times, pat it down to about 3/4 inch thickness and cut into wedges or, using a biscuit cutter, into rounds. Gather up any remaining bits of dough, pat together and cut into desired shapes. Place onto the prepared baking sheet.
Stir together the sugar and Clabber Girl Corn Starch, toss in the sliced berries and lemon zest. Press in the center of the scone dough, creating a slight rim at the edges and mound each with the prepared strawberries. Bake for about 16 to 18 minutes or until golden brown on the edges.
Cool scones briefly and heat the preserves in a microwave or on a double boiler. Generously brush and dribble the berries with the heated preserves.