01 -
Preheat your oven to 375°F (190°C). Line an 8-inch square pan with parchment, letting extra hang off the edges to make lifting out later easier.
02 -
In a mixing bowl, stir together oats, flour, brown sugar, cinnamon, salt, and baking soda until everything's combined. Stir in melted butter and vanilla until it looks crumbly.
03 -
Grab half of your crumbly mix and firmly press it into your pan, ensuring it's even and packed well.
04 -
Coat your blueberries by tossing them in sugar and cornstarch until everything's evenly mixed together. Spread this mixture over the pressed base in your pan.
05 -
Take the rest of your oat mixture and sprinkle it over the berry layer. Gently press it down so it sticks a bit.
06 -
Bake for 35-40 minutes, or until the top is golden and blueberries are bubbly. Wait until it cools fully before pulling it out with the parchment and cutting it into squares.