Preheat oven to 350°F. Grease a 9×13 baking dish and set it aside.
Prepare crumb topping: In a medium bowl combine flour, sugars, cinnamon, and salt. Add melted vegan butter and stir until fully incorporated. Cover and refrigerate for later.
In a large bowl, combine flour, sugar, salt, baking powder, and baking soda.
In a separate bowl, combine vegan eggs, plant-based buttermilk, plant milk, melted vegan butter, and vanilla extract. Whisk wet ingredients until well combined. Add wet ingredients to the dry ingredients and use a rubber spatula to stir until combined. Add in a handful of blueberries and gently fold into the mixture
Pour the batter into the greased baking dish. Add the remaining blueberries over the top. Remove the crumb topping from the fridge and crumble over the top of the blueberries and batter. Bake for about 35-45 minutes, until puffed and light golden brown.
Serve topped warm with maple syrup.
