Place all crust ingredients except maple syrup and vanilla in the bowl of a food processor. Process on low until oats have become a fine meal. Drizzle in maple syrup and vanilla while processing on low.

Transfer mixture to the prepared tart pan. Start by pressing in the sides followed by the bottom until it is evenly distributed. Sides of crust only need to go ¾ of the way up the side of the tart pan. Refrigerate until ready to fill.

Combine lemon juice and water in a small bowl. Stir in arrowroot starch until dissolved. Add half of the blueberries, organic cane sugar, lemon zest, and salt to a small saucepan over medium heat. Pour in the arrowroot slurry and stir to combine.

Stirring often with a rubber spatula, bring mixture to a boil then remove from heat. Add vanilla extract. Allow to cool.

Once cooled, fold in reserved blueberries with the cooked ones and transfer filling to the prepared pie crust.

Refrigerate for at least 3 hours before serving.