In a stand mixer, stir biscuit mix and butter together until the butter breaks apart into smaller pieces, about the size of peas.
Crack an egg into a liquid measuring cup and top it off with enough water to equal 3/4 cup. Whisk the mixture together and stream into dry ingredients with mixer on low. Once that is just incorporated, stir in cranberries and lemon zest.
Dump scone dough onto a well floured surface and press out to be an 8-10-inch circle, approximately. Cut into 8 triangles, just like you're cutting a pie. Place onto the baking mat and bake for 10-12 minutes or until puffed and lightly golden. Remove from oven and set aside to cool.
In a small bowl, combine powdered sugar and lemon juice until a thick but still runny glaze forms and spread over top scones. Serve warm or at room temperature.
Notes
Overspreading. If you are afraid that your lemon cranberry scones will spread, refrigerate the shaped scones for at least 15 minutes before baking.If you still find that your dough is spreading too much as it bakes, remove from the oven and press back into shape using a spatula. Then return to the oven to bake. Good luck!Freezing Baked. Bake scones as directed and cool. Do not top with icing. Freeze in an airtight bag or container for up to 4 months. To thaw, transfer the scones to the counter for a few hours or overnight in the fridge. Either warm in the microwave or in the oven, then top with icing!Freezing Unbaked. Once you are done cutting the dough into wedges, freeze on a plate or baking sheet for at least an hour. Then transfer to an airtight bag or container and freeze for up to 4 months. To bake, either bake from frozen, adding a few minutes to the baking time or thaw overnight and bake as normal.Overnight Instructions. To make these lemon cranberry scones the night before, follow the instructions, stopping after you cut the circle of dough into triangles. Cover and refrigerate overnight. When ready to bake, preheat your oven and continue where the instructions left off.