Preheat oven to 350°.
Prepare the filling: Heat the halved strawberries, maple syrup and water in a small pot over low to medium heat until softened.
Add in the chia seeds, cornstarch and lemon juice. Stir to combine. Remove from heat and let chill while preparing the crust.
Combine oats, oat flour, almond flour and baking powder in a large bowl.
In a separate bowl, combine nut butter, maple syrup and milk of choice.
Combine wet and dry ingredients.
Spray a 9 x 9 inch pan with coconut oil. Spread about ⅔ of the crust mixture into the baking dish and press into an even layer.
Pour the strawberry filling on top, making sure it's spread evenly.
Crumble the remaining ⅓ of the crust mixture on top.
Place the baking dish into the oven and bake at 350° for 45-60 minutes (to desired texture). Crumble should be golden brown.
Remove from oven and let cool for at least 1 hour before slicing.
Slice into 9 even squares and gently lift bars from pan with a small spatula.