Combine cake mix and flour in bowl of food processor; pulse a few times to combine.
Add cubed cold butter to processor and pulse until mixture resemble pea-sized crumbs.
(If you don’t have a food processor, cut in butter with a pastry cutter or two knives.)
Add mixture to medium bowl, mix in blueberries.
Add lemon zest to milk; add to flour mixture, stirring until mixture holds together.
Knead dough with well-floured hands to form a ball.
Place dough on prepared baking sheet and gently press down to form an 8- or 9-inch domed circle.
Cut circle into 8 wedges with a greased knife or bench scraper.
Chill scones for at least 15 minutes up to an hour in the refrigerator before baking.
Chilling the scone dough after forming helps keep the butter cold that creates that flaky texture.
When ready to bake, place 2 inches apart on parchment paper.
Bake in a preheated oven at 400°F for 20 to 25 minutes or until edges are starting to brown and centers are set.
Transfer scones to wire rack to cool completely. When cool, drizzle with glaze.
Bake from frozen option:
Freeze unbaked scones, wrapping individually and bake them off one or two at a time as needed.
Add a few minutes to your baking time when baking from frozen.