Preheat oven to 450°F (230°C) and line three baking sheets with parchment paper.
In a large bowl, mix baking mix, sugar, and softened butter until coarse crumbs form.
Add milk and lemon zest, stirring with a fork until a sticky dough forms.
Drop six spoonfuls of dough onto each baking sheet, spacing evenly, then press a well in the center of each with the back of a spoon.
Fill each well with blueberry pie filling evenly.
In a small bowl, combine flour, oats, cold butter, and lemon zest for crumble topping; blend until crumbly.
Sprinkle crumble topping over each pastry.
Bake pastries for 10 minutes or until golden around the edges.
Let pastries cool on baking sheets for several minutes, then transfer to a wire rack to cool completely.
Whisk powdered sugar with lemon juice until smooth to create glaze.
Drizzle lemon glaze over cooled pastries before serving.