Pre-heat oven to 350 degrees and grease an 8X8 pan with coconut oil. Line with parchment paper.
Mix together berries, lemon juice, and vanilla extract. Set aside
In a food processor, pulse oats, almond butter, coconut oil, coconut sugar, baking soda, vanilla extract, and salt until mealy (not a fine flour). Measure out ⅔ of the oat mixture and press into the bottom of the 8X8 pan.
Drain berries of excess liquid and toss with cornstarch. Gently press berries into the oat bar and top with remaining oat mixture.
Bake 40-45 minutes until golden brown. Allow to cool and cut into bars