Preheat oven to 350* F. Grease an 8x8-inch square pan and line it with parchment.
In a large bowl, combine flour, sugar, and baking powder. Stir to combine.
2 ¼ Cups All-Purpose Flour, ⅔ Cups Granulated Sugar, 1 teaspoon Baking Powder
Into the dry ingredients, add melted non-dairy butter, non-dairy milk, and vanilla. Mix with a spatula until the mixture is crumbly.
12 tablespoon Non-Dairy Butter, melted and cooled, 2 tablespoon Non-Dairy Milk, 1 teaspoon Vanilla Extract
Pour two-thirds of the crumble mixture into the prepared 8x8-inch square pan and use your fingers or an offset spatula to press it out into an even layer.
Then, pour the blueberry filling into the pan and spread it out evenly. Next, evenly top the blueberry mixture with the remaining crumble, breaking up any larger clumps as you scatter it out.
Bake the blueberry crumble bars in a 350*F oven for 35-38 minutes, or until the top is lightly brown and the filling is bubbling at the edges. Allow the bars to cool for at least an hour before slicing and serving.