Preheat your oven to 350 degrees F. Grease an 8x8 baking dish and set aside.
In a small bowl, add the blueberries and starch. Toss and set aside.
In a food processor, add the oat flour, sugar and diced butter. Pulse until a dough starts to form- about 4-5 pulses.
Add the oats, vanilla, salt, and cinnamon in the processor. Pulse until fully combined- another 5-6 pulses.
Pour 2/3 of the dough into your greased 8x8 baking dish. Grease your hands (you'll thank me) before pressing the dough down to form an even layer.
Pour the blueberries on top and lightly press down to incorporate them into the dough.
Add the rest of the dough on top (greasing your hands again!) and press it down as well. Sprinkle on the chocolate chips to finish.
Bake for 55-60 minutes or until the blueberries are nice and bubbly.
Let it cool completely before cutting the bars into 12 squares.