01 -
Turn the oven to 375°F (190°C) and line an 8-inch square dish with parchment, leaving some overhang to help lift it out later.
02 -
Mix together the oats, flour, sugar, cinnamon, salt, and baking soda in a bowl. Stir in the melted butter and vanilla until you get a crumbly dough.
03 -
Use half the crumb mixture and firmly press it into the bottom of the prepared pan in an even layer.
04 -
In a bowl, toss the blueberries with cornstarch and white sugar until they're fully coated. Spread this over the pressed base evenly.
05 -
Scatter the rest of the crumbly dough across the blueberries, pressing gently so it sticks together.
06 -
Bake for 35-40 minutes or until the top is golden and blueberries are bubbly. Cool completely before lifting out with the parchment and slicing into squares.