In a small saucepan, add sliced strawberries along with 1/4 cup maple syrup, 1 tablespoon lemon juice, lemon zest, and 1/4 teaspoon salt. Stir mixture over medium heat for 10 minutes or until strawberries begin to soften.
Once strawberries have softened and liquefied, add cornstarch to the mixture. Stir for an additional 1-2 minutes or until the mixture begins to thicken. Take off the heat, and set aside to cool.
Now, in a large bowl, combine oats, flour, baking soda, and remaining salt. Add remaining lemon juice, butter, and maple syrup. Use your hands to knead the mixture into a crumbled texture. Add 1-2 tablespoons more of butter if the mixture is too grainy. Set aside 1/2 cup of mixture.
Take the remaining oat mixture and press it into greased baking dish to form a crust. Layer strawberry filling on top of crust. Then add 1/2 cup remaining oat mixture and sprinkle over top of strawberry filling.
Place in oven for 25-30 minutes or until the crust is golden brown.
Set aside to cool for 30 minutes. Slice into bars and enjoy!