Preheat oven to 300 F.

To make the crust, place the first 3 ingredients in a food processor and pulse to chop oats.

Add the butter and pulse to combine.

Press the crust on the bottom of a parchment-lined 8 x 8 baking dish and flatten evenly with your hands. Bake for 10 minutes to set, then allow to cool.

Lower the oven temperature to 250 F.

To make the filling, place the first 5 ingredients in a bowl and beat to combine.

Fold in the blueberries.

Pour the batter on top of the crust and bake for 1 hour.

Cool and then chill until ready to serve.

Cut into squares and serve.*

*To get clean squares, wipe your knife between each slice.